From FPRI:
WHY WE SHOULD STUDY DEVELOPING NUCLEAR EARTH
PENETRATORS - AND WHY THEY ARE ACTUALLY STABILIZING
by Elbridge A. Colby
May 18, 2011
Elbridge Colby is a research analyst at CNA and has served
in several national security positions with the U.S.
Government, most recently with the Department of Defense
working on the follow-on to the START Treaty and as an
expert advisor to the Congressional Strategic Posture
Commission. The views expressed herein are his own and do
not necessarily represent the views of any institution with
which he is affiliated.
Available on the web and in pdf format at:
http://www.fpri.org/enotes/201105.colby.nuclear.html
WHY WE SHOULD STUDY DEVELOPING NUCLEAR EARTH
PENETRATORS - AND WHY THEY ARE ACTUALLY STABILIZING
by Elbridge A. Colby
With the ratification of the New START Treaty and the
associated political commitments made by the Administration
and Congress to modernize U.S. nuclear deterrent
capabilities, attention is beginning to shift towards the
shape of the future arsenal. Many questions remain: about
the threats which we need to deter, about what we need to
hold at risk in order to deter effectively, and about the
size and nature of the arsenal needed to meet those
requirements.
One of the most pressing questions is what the United States
can and should do about the growing ability of its most
plausible state adversaries, including North Korea and
Iran,[1] to locate their most valued assets underground in
facilities effectively immune from missile, air, or naval
attack. Estimates of the number of such "hard and deeply
buried targets" (HDBTs) have ranged from as low as 50 in
North Korea and Iran to as high as 10,000 worldwide
according to an influential study by the National Academy of
Sciences, citing the U.S. Defense Intelligence Agency (both
estimates in 2005).[2] While reliable numbers are
unavailable in the unclassified realm (and most likely also
in the classified, due to the extremely formidable
challenges of correctly identifying such facilities and
accurately ascertaining their characteristics), it seems
reasonable to assume that the number of significantly
hardened and buried facilities in countries of concern
stands at least in the hundreds and very possibly in the
thousands. In any case, what is essentially undisputed is
that potential adversaries such as North Korea and Iran are
increasingly able to locate or move their most valued assets
to underground depths beyond the effective reach of U.S.
action (assuming that the most deeply buried facilities
would be reserved primarily for the most important assets).
This is because current U.S. earth penetration capabilities
are insufficient to hold such facilities at risk. While the
U.S. fields conventional earth penetrators, "many of the
more important strategic hard and deeply buried targets are
beyond the reach of conventional explosive penetrating
weapons and can be held at risk of destruction only with
nuclear weapons,"[3] as the 2005 National Academy panel
reported. U.S. nuclear earth penetrator capabilities, on the
other hand, are also limited, and U.S. Government officials
have made clear that current U.S. nuclear weapons cannot
penetrate to the depths required to hold at risk the most
important HDBTs.[4]
EARTH PENETRATING WEAPONS ARE NEEDED
This is a serious problem. The core of deterrence lies in
being willing and able to destroy what your adversary most
values. Bluntly, we need to be able to say credibly that
"wherever you go, we can get at you." If enemies can make
themselves immune to retaliation, deterrence is seriously
compromised. Yet the trend among our potential adversaries
towards hiding underground, beyond the reach of our
weaponry, poses precisely this challenge.
This burrowing underground might not be so severe a problem
as to warrant developing nuclear earth penetrating weapons
(EPW) if we could rely on our ground forces eventually to
occupy and/or destroy bunkers. Thus the United States has
for the last two decades relied on the threat of regime
change and leadership accountability to deter WMD use by
rogue states. Because these states have generally had
comparatively limited WMD capabilities-and no nuclear
weapons-and could not strike the U.S. homeland, this threat
has been highly credible and quite effective. For example,
in 1990-1991 the United States could rely not only on a
response of massive retaliation, but also on threatening
Saddam Hussein and the Ba'ath leadership with regime change
and personal accountability if Iraqi forces used WMD against
Coalition forces, a combined threat that sufficed to deter
the Iraqis.
But this option is unlikely to be as feasible in the future.
This is because key potential U.S. adversaries, such as
North Korea and Iran, are today developing nuclear weapons
and fielding survivable delivery systems, such as mobile
ballistic missile systems, even as they are building more
hardened and deeply buried facilities.[5] This combination
of sanctuary and survivable striking power would allow these
countries to hide or shield their most valued assets beyond
the range of U.S. strikes while threatening the United
States and its allies with survivable nuclear delivery
systems. States so armed could shield their most valued
assets from U.S. strikes while holding the threat of nuclear
attack over Washington and allied capitals to deter any
attempt to disarm them or occupy their countries. Facing the
prospect of a nuclear strike in reaction to an attempt at
occupation, a future President would not be in as strong a
position to make a threat of the kind that Secretary of
State Baker made to Tariq Aziz and the Iraqi leadership: if
you use WMD against us, we will occupy your country and hold
you personally accountable. Instead, if current trends
continue, a country like North Korea will be able to place
its most valued assets in sanctuary underground beyond the
reach of our weaponry while ensuring, through survivable
nuclear and WMD forces, that we cannot sensibly attempt
occupation and regime change. This would mean that the
leadership of such a country might enjoy a degree of
effective immunity from U.S. reprisal.
Conversely, nuclear EPWs would be unnecessary if we could
safely and with good conscience rely on only the threat to
destroy unprotected cities and other soft targets to deter
the North Koreas of the world. But the threat to confine
ourselves to holding North Korean cities at risk in such a
situation might well be ineffective in swaying a leader such
as Kim Jong-Il, whose sensitivity to losses among his own
population when weighed against the preservation of his own
rule should not be overestimated. Moreover, we might
contemplate what Kim's response would be were we to attack
his cities when he might be hiding in a hardened bunker and
his mobile nuclear forces were dispersed. In light of North
Korea's retaliatory capabilities, does the United States
want to be forced to contemplate "trading" cities with a Kim
Jong-Il? Finally, it need hardly be stated that confining
ourselves to the option of attacking an adversary's cities
would be, to say the least, morally troubling.
The capability to destroy HDBTs, on the other hand, would
give the United States a more sensible option that would
enable us to get at what our adversaries most value while
avoiding the most serious pitfalls posed by occupation or
attacks upon cities as such. Unlike either of these
approaches, a formidable EPW capability would give us the
assured ability to target an opponent wherever he chose to
go, thus ensuring that he would never feel immune to our
retaliation and so giving him the strongest incentive to
moderate his own behavior. Even better, such a posture would
strengthen our basic pre-war deterrent, since a potential
adversary would know that he would always be vulnerable in a
conflict with the United States. This would, of course,
greatly increase the risks and potential costs of going to
war with the United States and so lower the chances of war
in the first place. This was why the United States, during
the Cold War and especially starting with the Carter
Administration, sought to develop the nuclear capabilities
needed to hold at risk the hardened and deeply buried sites
the Soviets were building in order to ensure that we could
target the Soviet leadership wherever they might go-even
after a Soviet first strike. It was the same logic applied
to more contemporary threats that drove the Clinton
Administration to generate the initial requirement for the
controversial robust nuclear earth penetrator in the 1990s.
Of course, an effective strike on an HDBT would require
accurate and timely intelligence, not only about the
location and nature of the facility, but also about its
contents. But the substantial difficulties of obtaining such
intelligence would not undermine our fundamental capability
to hold at risk an opponent in an HDBT, ensuring that an
adversary would know that he would always be vulnerable to
the exposure of his position-a well-grounded fear when the
signatures associated with the operations and movements of a
nation's leadership are considered. Moreover, assuming
substantial resolve on the part of the United States in the
face of a grave attack, there would be no necessary time
limitation on the acquisition of such intelligence.
EARTH PENETRATORS ACTUALLY FOSTER STABILITY
This deterrence requirement is relatively straightforward.
Many criticisms of the development of nuclear EPWs, however,
have focused on their allegedly destabilizing aspects, as in
the opposition to the Bush Administration's controversial
Robust Nuclear Earth Penetrator (RNEP) program.[6] Yet the
truth is that such weapons would actually foster stability
because they would reduce the incentives to strike early,
before a window of opportunity passes, and because they
would enable a retaliatory strike posture.
If strategic stability is given its traditional definition
of weapons and postures that mitigate incentives to strike
first and/or fast in a crisis and that reduce the
probability of war, then earth penetrating weapons are not
destabilizing. Quite the contrary. Because effective EPWs
would enable the United States to hit an opponent whenever
and wherever it chose to do so, they would minimize any
pressures on the U.S. to strike in a perceived window of
opportunity while an enemy or his valued asset was still
aboveground or in a vulnerable underground facility. A
principal reason to strike first is to take advantage of
opportunities while they exist, opportunities such as the
ability to take out an adversary's valued assets while they
remain vulnerable to U.S. strikes. Think, for instance, of
the pressures that a U.S. leader might face in a variant of
the 2003 attempted decapitating strike against Saddam
Hussein if the President thought there were a serious chance
the opponent might use WMD-and then think of the response of
the opponent in the wake of such a decapitation attempt.
With EPW weapons, it would be less likely that a President
would be boxed in by the hellish choice of "strike now, or
lose the opportunity entirely" because there would be
nowhere that an opponent could safely escape American
action. An EPW capability would thus mitigate the window of
opportunity quandary and so allow the President to wait, a
vital component of stability. More broadly, an EPW
capability would strengthen stability by giving U.S.
decision-makers greater confidence in the general
effectiveness of the American retaliatory capability, since
there would be no sanctuary from it. This would give greater
strength to the overall American deterrent, thereby lowering
the probability of aggression against U.S. interests and
war.
Another important consideration in the stability equation is
the confidence that Russia and China have in the
survivability and effectiveness of their retaliatory force
in light of U.S. assets. U.S. capabilities that could help
give the United States a disarming first strike capability
could well encourage Moscow or Beijing to adopt far less
deliberate launch postures, in turn increasing the
possibilities of catastrophe. Yet EPWs would not add
significant counterforce capability against Russia or
China's retaliatory forces to the U.S. arsenal. Deployed
mobile land or sea-based ballistic missiles as well as
mobile or otherwise survivable command and control assets
would not be more easily targeted because of an earth
penetration capability. Thus the United States would not
gain any added benefit from striking first in an attempt to
disarm an opponent. Moreover, the United States could take
additional steps to minimize disruptions in strategic
relations with Moscow and Beijing; for instance, the United
States might unilaterally commit to limiting the number of
such weapons produced to limit their impact on strategic
stability with Russia and China.
Finally, EPWs would not lower the "threshold" for nuclear
use-a nuclear strike would remain the extraordinarily grave
step that it is today. Indeed, the very fact that effective
nuclear EPWs would necessarily be very "dirty" in terms of
radioactive fallout would ensure that no President would
authorize their use except in the gravest circumstances.[7]
EARTH PENETRATORS DO NOT NEED TO BE NUCLEAR,
BUT NUCLEAR VARIANTS SHOULD NOT BE RULED OUT
The requirement of deterrence with respect to HDBTs is that
the United States needs to be able to hold at risk from afar
whatever an opponent values, even if he goes deep
underground. This does not perforce require that such
capabilities be nuclear; indeed, the use of conventional
weapons to disable or effectively destroy HDBTs by closing
off airshafts, entrances, and other vulnerable points would
of course be a preferable approach. U.S. opponents, however,
are fully aware of these conventional capabilities and must
be expected to anticipate U.S. attempts to close off tunnel
entrances and ventilation systems and to adapt to such a
threat by such measures as multiplying entrances/exits,
airshafts, and communication links and by the use of decoys,
among other tactics. Moreover, as the National Academy of
Sciences report found, there are stark physical limitations
on the destructive power of conventional munitions as earth
penetrators. This means that, in order to defeat some HDBTs,
especially the most hardened and valuable ones, the
explosive power that only a nuclear weapon can provide might
be required in order to destroy the facility. Indeed, even
a nuclear earth penetrator strike might well need to be
accompanied by conventional strikes to close off exits
and/or to prepare the target area in advance of a laydown
employment of more vulnerable types of nuclear EPWs,
including those designed to burrow more deeply before
detonating.
While the technical characteristics of an effective EPW
capability should not be too sharply defined in advance, the
key is that nuclear options for EPWs should not be excluded
from serious consideration. Prudence dictates, therefore,
that the U.S. Government should carefully study the
feasibility and utility of nuclear EPWs, specifically by
ordering the National Laboratories to study the issue. One
concrete step that Congress could take would be to allow the
National Laboratories to conduct simulated "sled tests" to
determine how a nuclear payload would operate against HDBTs.
Congress in the FY2006 Defense Authorization Act prohibited
the Laboratories from conducting such tests, in effect
blocking off research into the nuclear option.[8]
In order to minimize any negative political repercussions
associated with the development of a nuclear EPW, it could
be based on existing weapons, especially the B-61 Mod-11 or
the more powerful B-83 nuclear gravity bombs; indeed, some
work has already been done in this direction.[9] Focusing
initial nuclear EPW work on gravity bombs would also lessen
concerns in Moscow and Beijing, as bombers are far less
suitable as first strike weapons than are fast-flying
ballistic missiles.[10] To further assuage concerns,
modifications could be trammeled to ensure that additional
nuclear testing would not be required to certify the weapon
while pursuing necessary hardening and other improvements.
GETTING PAST THE POLITICS TO MAINTAIN DETERRENCE
The last time a study to look into a nuclear EPW was
proposed, the idea fell victim to the political tempest
surrounding the 2001 Nuclear Posture Review, the emphasis on
preemption in the 2002 National Security Strategy, and the
2003 war against Iraq. A nuclear EPW ended up looking like a
symbol and tool of aggression, preemption, and a policy of
first strike. This was unfortunate, as it distorted the
realities of the issue. An effective EPW capability-whether
conventional, nuclear, or both-is crucial for deterrence and
stability. Indeed, the requirement for such a capability is
a logical deduction from the traditional American approach
to nuclear policy, one that stretches back into the Cold
War, when the United States initiated development of nuclear
EPWs to ensure that the Soviet leadership could never feel
immune from U.S. retaliation, and forward to the Clinton
Administration's decision to initiate work on a robust
nuclear earth penetrator. Correctly couching consideration
of a nuclear EPW in this context cannot but help to win it a
fairer hearing.
Beyond debates about stability, however, critics of a
nuclear EPW have also argued that the development by the
United States of any new nuclear weapons capabilities would
undermine nonproliferation efforts by exposing Washington to
charges of hypocrisy. How, runs this line of argument, would
the United States be able to ask non-nuclear weapons states
to forswear pursuing their own nuclear arsenals-and support
firm efforts to prevent others from acquiring them-if the
United States is itself modernizing its arsenal? This debate
touches on a much larger set of issues concerning why
nations acquire nuclear weapons and the nature of the
international system, but the essence of the problem with
this critique is that it vastly overstates the influence
that incremental U.S. nuclear policy decisions such as the
one advocated here have on other nations' calculus as to
whether to obtain nuclear weapons of their own. Moreover, to
the extent that there are concerns regarding the
consequences of development of a nuclear EPW, the United
States could mount a vigorous public diplomacy initiative to
explain that the development was driven not by pursuit of a
domineering, disarming capability but rather by the need to
maintain an effective deterrent to preserve stability in
light of changing conditions.
The question of how technically to develop a nuclear EPW
while maintaining U.S. commitments to restraint presents
another set of challenges. It is true that developing and
deploying a nuclear EPW might require a change in the U.S.
policy, as laid out in the 2010 Nuclear Posture Review, that
the United States would not develop new nuclear warheads or
pursue new military missions or new capabilities for nuclear
weapons. Of course, if an effective nuclear EPW could be
entirely based on existing systems, then no change in U.S.
policy on nuclear weapons development would be entailed. (A
nuclear EPW would not be a new capability because the
existing B61-11 weapon is a penetrator.) But it is possible
that, in order to field a credibly effective nuclear EPW,
new capabilities might need to be pursued. For instance, if
potential adversaries continue digging further underground,
the United States will likely need to develop effective
burrowing devices to "open the door" for follow-on weapons
to couple their blasts more effectively to the target. This
development would entail a change in national policy. Yet
the change involved would be relatively modest, constituting
an adaptation of the existing framework of deterrence to new
technical and geostrategic realities rather than a basic
change in our fundamental approach. More to the point, a
rigid "no change" policy cannot be tenable if, as we must
realize, nuclear deterrence will remain a cornerstone of our
security for the foreseeable future. The instinct to keep
nuclear competition in check is laudable, but this does not
necessitate a straitjacket on adaptation, which is what a
nuclear EPW would be.
Ultimately, deterrence remains the best way to avoid war
while protecting our core interests. Deterrence rests on the
ability and the willingness to strike what one's opponent
most values wherever they are-no matter how long it takes.
Weapons, postures, and strategies that contribute to this
ability are to be commended and pursued, even if they at
first glance seem frightening, for it may be the very
qualities that make them frightening that also make them
effective, and therefore stabilizing.
GLOSSARY OF TERMS
Earth Penetrating Weapons: A weapon designed to penetrate
into soil, rock, concrete, or other material to deliver a
weapon to a target buried in the earth.
Hard and deeply buried targets: Intentionally hardened and
buried facilities used to conceal and protect a state's
leaders, military and industrial personnel, weapons,
equipment, and other assets and activities. Ranging from
hardened, surface bunker complexes to tunnel facilities deep
underground, HDBTs are typically large, complex, and well
concealed, incorporating strong physical security, modern
air defenses, protective siting, multifaceted
communications, and other important features that make many
of them able to survive attack by conventional weapons.
Sled test: A test platform that slides along rails designed
to test equipment such as missiles and bombs for collection
on a variety of characteristics, including results of
impact.
----------------------------------------------------------
Notes
[1] See Christopher Ford, "Conventional 'Replacement' of
Nuclear Weapons," at
http://www.newparadigmsforum.com/NPFtestsite/?p=546.
[2] For the low figure, see Jeffrey Lewis, "How Many Rogue
State Hard and Deeply Buried Targets?" ArmsControlWonk.com,
May 20, 2005, at
http://lewis.armscontrolwonk.com/archive/511/how-many-rogue-state-hard-and-deeply-buried-targets. For the high figure,
see National Research Council of the National Academies,
Committee on the Effects of Nuclear Earth-Penetrator and
Other Weapons, Effects of Nuclear Earth-Penetrator and Other
Weapons, Washington, DC: National Academies Press, 2005, 14,
available at
http://www.nap.edu/openbook.php?record_id=11282&page=14.
[3] Ibid., 1.
[4] Statement of Linton F. Brooks, Acting Under Secretary of
Energy and Administrator for National Security, National
Nuclear Security Administration, U.S. Department of Energy,
before the Subcomittee on Strategic Forces, Senate Committee
on Armed Services, April 8, 2003, at
http://armed-services.senate.gov/statemnt/2003/April/Brooks.pdf.
[5] See, e.g., Daniel A. Pinkston, The North Korean
Ballistic Missile Program. Carlisle, PA: Strategic Studies
Institute,
http://www.strategicstudiesinstitute.army.mil/pubs/display.cfm?pubID=842,
and, for Iran,
http://www.fas.org/programs/ssp/man/militarysumfolder/shahab-3.html.
[6] See, for instance, Daryl G. Kimball, "Replacement
Nuclear Warheads? Buyer Beware," Arms Control Today, May
2005, available at
http://www.armscontrol.org/act/2005_05/focus.
[7] See Chapter 6, "Human and Environmental Effects," of the
National Academies study for an analysis of the severe
consequences of even a low-yield nuclear earth penetrator.
[8] See the National Defense Authorization Act for Fiscal
Year 2006, Report of the Committee on Armed Services of the
House of Representatives, 463, available at
http://frwebgate.access.gpo.gov/cgi-bin/getdoc.cgi?dbname=109_cong_reports&docid=f:hr089.109.pdf.
For an account of the history of the termination of RNEP,
see Jeffrey Lewis, "NNSA Denies Axeing RNEP," November 15,
2005,
http://lewis.armscontrolwonk.com/archive/855/nnsa-denies-dropping-rnep.
[9] See "Robust Nuclear Earth Penetrator" at
GlobalSecurity.com at
http://www.globalsecurity.org/wmd/systems/rnep.htm.
[10] This would not be to exclude consideration of a nuclear
EPW on a ballistic missile, but simply to investigate
whether a gravity bomb option might be sufficient for
deterrence and on technical grounds.
----------------------------------------------------------
Copyright Foreign Policy Research Institute
(http://www.fpri.org/).
WHY WE SHOULD STUDY DEVELOPING NUCLEAR EARTH
PENETRATORS - AND WHY THEY ARE ACTUALLY STABILIZING
by Elbridge A. Colby
May 18, 2011
Elbridge Colby is a research analyst at CNA and has served
in several national security positions with the U.S.
Government, most recently with the Department of Defense
working on the follow-on to the START Treaty and as an
expert advisor to the Congressional Strategic Posture
Commission. The views expressed herein are his own and do
not necessarily represent the views of any institution with
which he is affiliated.
Available on the web and in pdf format at:
http://www.fpri.org/enotes/201105.colby.nuclear.html
WHY WE SHOULD STUDY DEVELOPING NUCLEAR EARTH
PENETRATORS - AND WHY THEY ARE ACTUALLY STABILIZING
by Elbridge A. Colby
With the ratification of the New START Treaty and the
associated political commitments made by the Administration
and Congress to modernize U.S. nuclear deterrent
capabilities, attention is beginning to shift towards the
shape of the future arsenal. Many questions remain: about
the threats which we need to deter, about what we need to
hold at risk in order to deter effectively, and about the
size and nature of the arsenal needed to meet those
requirements.
One of the most pressing questions is what the United States
can and should do about the growing ability of its most
plausible state adversaries, including North Korea and
Iran,[1] to locate their most valued assets underground in
facilities effectively immune from missile, air, or naval
attack. Estimates of the number of such "hard and deeply
buried targets" (HDBTs) have ranged from as low as 50 in
North Korea and Iran to as high as 10,000 worldwide
according to an influential study by the National Academy of
Sciences, citing the U.S. Defense Intelligence Agency (both
estimates in 2005).[2] While reliable numbers are
unavailable in the unclassified realm (and most likely also
in the classified, due to the extremely formidable
challenges of correctly identifying such facilities and
accurately ascertaining their characteristics), it seems
reasonable to assume that the number of significantly
hardened and buried facilities in countries of concern
stands at least in the hundreds and very possibly in the
thousands. In any case, what is essentially undisputed is
that potential adversaries such as North Korea and Iran are
increasingly able to locate or move their most valued assets
to underground depths beyond the effective reach of U.S.
action (assuming that the most deeply buried facilities
would be reserved primarily for the most important assets).
This is because current U.S. earth penetration capabilities
are insufficient to hold such facilities at risk. While the
U.S. fields conventional earth penetrators, "many of the
more important strategic hard and deeply buried targets are
beyond the reach of conventional explosive penetrating
weapons and can be held at risk of destruction only with
nuclear weapons,"[3] as the 2005 National Academy panel
reported. U.S. nuclear earth penetrator capabilities, on the
other hand, are also limited, and U.S. Government officials
have made clear that current U.S. nuclear weapons cannot
penetrate to the depths required to hold at risk the most
important HDBTs.[4]
EARTH PENETRATING WEAPONS ARE NEEDED
This is a serious problem. The core of deterrence lies in
being willing and able to destroy what your adversary most
values. Bluntly, we need to be able to say credibly that
"wherever you go, we can get at you." If enemies can make
themselves immune to retaliation, deterrence is seriously
compromised. Yet the trend among our potential adversaries
towards hiding underground, beyond the reach of our
weaponry, poses precisely this challenge.
This burrowing underground might not be so severe a problem
as to warrant developing nuclear earth penetrating weapons
(EPW) if we could rely on our ground forces eventually to
occupy and/or destroy bunkers. Thus the United States has
for the last two decades relied on the threat of regime
change and leadership accountability to deter WMD use by
rogue states. Because these states have generally had
comparatively limited WMD capabilities-and no nuclear
weapons-and could not strike the U.S. homeland, this threat
has been highly credible and quite effective. For example,
in 1990-1991 the United States could rely not only on a
response of massive retaliation, but also on threatening
Saddam Hussein and the Ba'ath leadership with regime change
and personal accountability if Iraqi forces used WMD against
Coalition forces, a combined threat that sufficed to deter
the Iraqis.
But this option is unlikely to be as feasible in the future.
This is because key potential U.S. adversaries, such as
North Korea and Iran, are today developing nuclear weapons
and fielding survivable delivery systems, such as mobile
ballistic missile systems, even as they are building more
hardened and deeply buried facilities.[5] This combination
of sanctuary and survivable striking power would allow these
countries to hide or shield their most valued assets beyond
the range of U.S. strikes while threatening the United
States and its allies with survivable nuclear delivery
systems. States so armed could shield their most valued
assets from U.S. strikes while holding the threat of nuclear
attack over Washington and allied capitals to deter any
attempt to disarm them or occupy their countries. Facing the
prospect of a nuclear strike in reaction to an attempt at
occupation, a future President would not be in as strong a
position to make a threat of the kind that Secretary of
State Baker made to Tariq Aziz and the Iraqi leadership: if
you use WMD against us, we will occupy your country and hold
you personally accountable. Instead, if current trends
continue, a country like North Korea will be able to place
its most valued assets in sanctuary underground beyond the
reach of our weaponry while ensuring, through survivable
nuclear and WMD forces, that we cannot sensibly attempt
occupation and regime change. This would mean that the
leadership of such a country might enjoy a degree of
effective immunity from U.S. reprisal.
Conversely, nuclear EPWs would be unnecessary if we could
safely and with good conscience rely on only the threat to
destroy unprotected cities and other soft targets to deter
the North Koreas of the world. But the threat to confine
ourselves to holding North Korean cities at risk in such a
situation might well be ineffective in swaying a leader such
as Kim Jong-Il, whose sensitivity to losses among his own
population when weighed against the preservation of his own
rule should not be overestimated. Moreover, we might
contemplate what Kim's response would be were we to attack
his cities when he might be hiding in a hardened bunker and
his mobile nuclear forces were dispersed. In light of North
Korea's retaliatory capabilities, does the United States
want to be forced to contemplate "trading" cities with a Kim
Jong-Il? Finally, it need hardly be stated that confining
ourselves to the option of attacking an adversary's cities
would be, to say the least, morally troubling.
The capability to destroy HDBTs, on the other hand, would
give the United States a more sensible option that would
enable us to get at what our adversaries most value while
avoiding the most serious pitfalls posed by occupation or
attacks upon cities as such. Unlike either of these
approaches, a formidable EPW capability would give us the
assured ability to target an opponent wherever he chose to
go, thus ensuring that he would never feel immune to our
retaliation and so giving him the strongest incentive to
moderate his own behavior. Even better, such a posture would
strengthen our basic pre-war deterrent, since a potential
adversary would know that he would always be vulnerable in a
conflict with the United States. This would, of course,
greatly increase the risks and potential costs of going to
war with the United States and so lower the chances of war
in the first place. This was why the United States, during
the Cold War and especially starting with the Carter
Administration, sought to develop the nuclear capabilities
needed to hold at risk the hardened and deeply buried sites
the Soviets were building in order to ensure that we could
target the Soviet leadership wherever they might go-even
after a Soviet first strike. It was the same logic applied
to more contemporary threats that drove the Clinton
Administration to generate the initial requirement for the
controversial robust nuclear earth penetrator in the 1990s.
Of course, an effective strike on an HDBT would require
accurate and timely intelligence, not only about the
location and nature of the facility, but also about its
contents. But the substantial difficulties of obtaining such
intelligence would not undermine our fundamental capability
to hold at risk an opponent in an HDBT, ensuring that an
adversary would know that he would always be vulnerable to
the exposure of his position-a well-grounded fear when the
signatures associated with the operations and movements of a
nation's leadership are considered. Moreover, assuming
substantial resolve on the part of the United States in the
face of a grave attack, there would be no necessary time
limitation on the acquisition of such intelligence.
EARTH PENETRATORS ACTUALLY FOSTER STABILITY
This deterrence requirement is relatively straightforward.
Many criticisms of the development of nuclear EPWs, however,
have focused on their allegedly destabilizing aspects, as in
the opposition to the Bush Administration's controversial
Robust Nuclear Earth Penetrator (RNEP) program.[6] Yet the
truth is that such weapons would actually foster stability
because they would reduce the incentives to strike early,
before a window of opportunity passes, and because they
would enable a retaliatory strike posture.
If strategic stability is given its traditional definition
of weapons and postures that mitigate incentives to strike
first and/or fast in a crisis and that reduce the
probability of war, then earth penetrating weapons are not
destabilizing. Quite the contrary. Because effective EPWs
would enable the United States to hit an opponent whenever
and wherever it chose to do so, they would minimize any
pressures on the U.S. to strike in a perceived window of
opportunity while an enemy or his valued asset was still
aboveground or in a vulnerable underground facility. A
principal reason to strike first is to take advantage of
opportunities while they exist, opportunities such as the
ability to take out an adversary's valued assets while they
remain vulnerable to U.S. strikes. Think, for instance, of
the pressures that a U.S. leader might face in a variant of
the 2003 attempted decapitating strike against Saddam
Hussein if the President thought there were a serious chance
the opponent might use WMD-and then think of the response of
the opponent in the wake of such a decapitation attempt.
With EPW weapons, it would be less likely that a President
would be boxed in by the hellish choice of "strike now, or
lose the opportunity entirely" because there would be
nowhere that an opponent could safely escape American
action. An EPW capability would thus mitigate the window of
opportunity quandary and so allow the President to wait, a
vital component of stability. More broadly, an EPW
capability would strengthen stability by giving U.S.
decision-makers greater confidence in the general
effectiveness of the American retaliatory capability, since
there would be no sanctuary from it. This would give greater
strength to the overall American deterrent, thereby lowering
the probability of aggression against U.S. interests and
war.
Another important consideration in the stability equation is
the confidence that Russia and China have in the
survivability and effectiveness of their retaliatory force
in light of U.S. assets. U.S. capabilities that could help
give the United States a disarming first strike capability
could well encourage Moscow or Beijing to adopt far less
deliberate launch postures, in turn increasing the
possibilities of catastrophe. Yet EPWs would not add
significant counterforce capability against Russia or
China's retaliatory forces to the U.S. arsenal. Deployed
mobile land or sea-based ballistic missiles as well as
mobile or otherwise survivable command and control assets
would not be more easily targeted because of an earth
penetration capability. Thus the United States would not
gain any added benefit from striking first in an attempt to
disarm an opponent. Moreover, the United States could take
additional steps to minimize disruptions in strategic
relations with Moscow and Beijing; for instance, the United
States might unilaterally commit to limiting the number of
such weapons produced to limit their impact on strategic
stability with Russia and China.
Finally, EPWs would not lower the "threshold" for nuclear
use-a nuclear strike would remain the extraordinarily grave
step that it is today. Indeed, the very fact that effective
nuclear EPWs would necessarily be very "dirty" in terms of
radioactive fallout would ensure that no President would
authorize their use except in the gravest circumstances.[7]
EARTH PENETRATORS DO NOT NEED TO BE NUCLEAR,
BUT NUCLEAR VARIANTS SHOULD NOT BE RULED OUT
The requirement of deterrence with respect to HDBTs is that
the United States needs to be able to hold at risk from afar
whatever an opponent values, even if he goes deep
underground. This does not perforce require that such
capabilities be nuclear; indeed, the use of conventional
weapons to disable or effectively destroy HDBTs by closing
off airshafts, entrances, and other vulnerable points would
of course be a preferable approach. U.S. opponents, however,
are fully aware of these conventional capabilities and must
be expected to anticipate U.S. attempts to close off tunnel
entrances and ventilation systems and to adapt to such a
threat by such measures as multiplying entrances/exits,
airshafts, and communication links and by the use of decoys,
among other tactics. Moreover, as the National Academy of
Sciences report found, there are stark physical limitations
on the destructive power of conventional munitions as earth
penetrators. This means that, in order to defeat some HDBTs,
especially the most hardened and valuable ones, the
explosive power that only a nuclear weapon can provide might
be required in order to destroy the facility. Indeed, even
a nuclear earth penetrator strike might well need to be
accompanied by conventional strikes to close off exits
and/or to prepare the target area in advance of a laydown
employment of more vulnerable types of nuclear EPWs,
including those designed to burrow more deeply before
detonating.
While the technical characteristics of an effective EPW
capability should not be too sharply defined in advance, the
key is that nuclear options for EPWs should not be excluded
from serious consideration. Prudence dictates, therefore,
that the U.S. Government should carefully study the
feasibility and utility of nuclear EPWs, specifically by
ordering the National Laboratories to study the issue. One
concrete step that Congress could take would be to allow the
National Laboratories to conduct simulated "sled tests" to
determine how a nuclear payload would operate against HDBTs.
Congress in the FY2006 Defense Authorization Act prohibited
the Laboratories from conducting such tests, in effect
blocking off research into the nuclear option.[8]
In order to minimize any negative political repercussions
associated with the development of a nuclear EPW, it could
be based on existing weapons, especially the B-61 Mod-11 or
the more powerful B-83 nuclear gravity bombs; indeed, some
work has already been done in this direction.[9] Focusing
initial nuclear EPW work on gravity bombs would also lessen
concerns in Moscow and Beijing, as bombers are far less
suitable as first strike weapons than are fast-flying
ballistic missiles.[10] To further assuage concerns,
modifications could be trammeled to ensure that additional
nuclear testing would not be required to certify the weapon
while pursuing necessary hardening and other improvements.
GETTING PAST THE POLITICS TO MAINTAIN DETERRENCE
The last time a study to look into a nuclear EPW was
proposed, the idea fell victim to the political tempest
surrounding the 2001 Nuclear Posture Review, the emphasis on
preemption in the 2002 National Security Strategy, and the
2003 war against Iraq. A nuclear EPW ended up looking like a
symbol and tool of aggression, preemption, and a policy of
first strike. This was unfortunate, as it distorted the
realities of the issue. An effective EPW capability-whether
conventional, nuclear, or both-is crucial for deterrence and
stability. Indeed, the requirement for such a capability is
a logical deduction from the traditional American approach
to nuclear policy, one that stretches back into the Cold
War, when the United States initiated development of nuclear
EPWs to ensure that the Soviet leadership could never feel
immune from U.S. retaliation, and forward to the Clinton
Administration's decision to initiate work on a robust
nuclear earth penetrator. Correctly couching consideration
of a nuclear EPW in this context cannot but help to win it a
fairer hearing.
Beyond debates about stability, however, critics of a
nuclear EPW have also argued that the development by the
United States of any new nuclear weapons capabilities would
undermine nonproliferation efforts by exposing Washington to
charges of hypocrisy. How, runs this line of argument, would
the United States be able to ask non-nuclear weapons states
to forswear pursuing their own nuclear arsenals-and support
firm efforts to prevent others from acquiring them-if the
United States is itself modernizing its arsenal? This debate
touches on a much larger set of issues concerning why
nations acquire nuclear weapons and the nature of the
international system, but the essence of the problem with
this critique is that it vastly overstates the influence
that incremental U.S. nuclear policy decisions such as the
one advocated here have on other nations' calculus as to
whether to obtain nuclear weapons of their own. Moreover, to
the extent that there are concerns regarding the
consequences of development of a nuclear EPW, the United
States could mount a vigorous public diplomacy initiative to
explain that the development was driven not by pursuit of a
domineering, disarming capability but rather by the need to
maintain an effective deterrent to preserve stability in
light of changing conditions.
The question of how technically to develop a nuclear EPW
while maintaining U.S. commitments to restraint presents
another set of challenges. It is true that developing and
deploying a nuclear EPW might require a change in the U.S.
policy, as laid out in the 2010 Nuclear Posture Review, that
the United States would not develop new nuclear warheads or
pursue new military missions or new capabilities for nuclear
weapons. Of course, if an effective nuclear EPW could be
entirely based on existing systems, then no change in U.S.
policy on nuclear weapons development would be entailed. (A
nuclear EPW would not be a new capability because the
existing B61-11 weapon is a penetrator.) But it is possible
that, in order to field a credibly effective nuclear EPW,
new capabilities might need to be pursued. For instance, if
potential adversaries continue digging further underground,
the United States will likely need to develop effective
burrowing devices to "open the door" for follow-on weapons
to couple their blasts more effectively to the target. This
development would entail a change in national policy. Yet
the change involved would be relatively modest, constituting
an adaptation of the existing framework of deterrence to new
technical and geostrategic realities rather than a basic
change in our fundamental approach. More to the point, a
rigid "no change" policy cannot be tenable if, as we must
realize, nuclear deterrence will remain a cornerstone of our
security for the foreseeable future. The instinct to keep
nuclear competition in check is laudable, but this does not
necessitate a straitjacket on adaptation, which is what a
nuclear EPW would be.
Ultimately, deterrence remains the best way to avoid war
while protecting our core interests. Deterrence rests on the
ability and the willingness to strike what one's opponent
most values wherever they are-no matter how long it takes.
Weapons, postures, and strategies that contribute to this
ability are to be commended and pursued, even if they at
first glance seem frightening, for it may be the very
qualities that make them frightening that also make them
effective, and therefore stabilizing.
GLOSSARY OF TERMS
Earth Penetrating Weapons: A weapon designed to penetrate
into soil, rock, concrete, or other material to deliver a
weapon to a target buried in the earth.
Hard and deeply buried targets: Intentionally hardened and
buried facilities used to conceal and protect a state's
leaders, military and industrial personnel, weapons,
equipment, and other assets and activities. Ranging from
hardened, surface bunker complexes to tunnel facilities deep
underground, HDBTs are typically large, complex, and well
concealed, incorporating strong physical security, modern
air defenses, protective siting, multifaceted
communications, and other important features that make many
of them able to survive attack by conventional weapons.
Sled test: A test platform that slides along rails designed
to test equipment such as missiles and bombs for collection
on a variety of characteristics, including results of
impact.
----------------------------------------------------------
Notes
[1] See Christopher Ford, "Conventional 'Replacement' of
Nuclear Weapons," at
http://www.newparadigmsforum.com/NPFtestsite/?p=546.
[2] For the low figure, see Jeffrey Lewis, "How Many Rogue
State Hard and Deeply Buried Targets?" ArmsControlWonk.com,
May 20, 2005, at
http://lewis.armscontrolwonk.com/archive/511/how-many-rogue-state-hard-and-deeply-buried-targets. For the high figure,
see National Research Council of the National Academies,
Committee on the Effects of Nuclear Earth-Penetrator and
Other Weapons, Effects of Nuclear Earth-Penetrator and Other
Weapons, Washington, DC: National Academies Press, 2005, 14,
available at
http://www.nap.edu/openbook.php?record_id=11282&page=14.
[3] Ibid., 1.
[4] Statement of Linton F. Brooks, Acting Under Secretary of
Energy and Administrator for National Security, National
Nuclear Security Administration, U.S. Department of Energy,
before the Subcomittee on Strategic Forces, Senate Committee
on Armed Services, April 8, 2003, at
http://armed-services.senate.gov/statemnt/2003/April/Brooks.pdf.
[5] See, e.g., Daniel A. Pinkston, The North Korean
Ballistic Missile Program. Carlisle, PA: Strategic Studies
Institute,
http://www.strategicstudiesinstitute.army.mil/pubs/display.cfm?pubID=842,
and, for Iran,
http://www.fas.org/programs/ssp/man/militarysumfolder/shahab-3.html.
[6] See, for instance, Daryl G. Kimball, "Replacement
Nuclear Warheads? Buyer Beware," Arms Control Today, May
2005, available at
http://www.armscontrol.org/act/2005_05/focus.
[7] See Chapter 6, "Human and Environmental Effects," of the
National Academies study for an analysis of the severe
consequences of even a low-yield nuclear earth penetrator.
[8] See the National Defense Authorization Act for Fiscal
Year 2006, Report of the Committee on Armed Services of the
House of Representatives, 463, available at
http://frwebgate.access.gpo.gov/cgi-bin/getdoc.cgi?dbname=109_cong_reports&docid=f:hr089.109.pdf.
For an account of the history of the termination of RNEP,
see Jeffrey Lewis, "NNSA Denies Axeing RNEP," November 15,
2005,
http://lewis.armscontrolwonk.com/archive/855/nnsa-denies-dropping-rnep.
[9] See "Robust Nuclear Earth Penetrator" at
GlobalSecurity.com at
http://www.globalsecurity.org/wmd/systems/rnep.htm.
[10] This would not be to exclude consideration of a nuclear
EPW on a ballistic missile, but simply to investigate
whether a gravity bomb option might be sufficient for
deterrence and on technical grounds.
----------------------------------------------------------
Copyright Foreign Policy Research Institute
(http://www.fpri.org/).
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