June 2019, ScientificAmerican.com 67rines at sea. And this logic certainly does not apply to an adver-
sary whose intent is not to target U.S. retaliatory capability in the
first place, such as North Korea or even China. Those nations’
missile arsenals are too small and inaccurate to mount an effec-
tive strike against U.S. nuclear forces. Instead they would target
cities or other large, unprotected sites. Therefore, missile defense
is unlikely to offer anything that adds to the deterrence currently
provided by U.S. forces.
The Missile Defense Review also argues that the U.S. needs a
defensive shield so an adversary’s missile threats cannot force
this nation away from taking military actions in its own interests
or on behalf of an ally. But to make U.S. decision makers confi-
dent enough to ignore adversarial threats, a system such as the
GMD needs to demonstrate high effectiveness, and it has not.
At its core, missile defense is meant to defeat a nuclear attack
if deterrence were to fail. While this is where the “some is better
than none” argument is the most persuasive, for any realistic sce-
nario, missile defense will likely do very little. Even if the system’s
ability to deal with real-world complexities such as countermea-
sures were greatly improved, a nuclear attack will still present
enormous risks. For example, if the system achieved an improba-
bly high 95 percent effectiveness against one missile, in an attack
by just five missiles there is still a one-in-four chance of at least
one nuclear warhead penetrating the defense. The likelihood of a
city being destroyed would be higher than correctly predicting
the roll of a die. The effectiveness against a real attack is likely to
be much lower.
What missile defenses may actually do is get in the way of reduc-
ing the nuclear threat faced by the U.S. or even increase it. As long
as nations such as Russia and China continue to rely on strategic ar-
senals for deterrence, pursuing defenses that appear to threaten
that deterrent—or that lay the groundwork for a system that may
threaten it in the future—will at best hinder nuclear reductions.
At worst these efforts will lead to the growth of more offensive
weapons designed to overwhelm the defense and reduce stability
by increasing the incentive to launch missiles first in a crisis.
There is growing evidence that global powers are already re-
turning to this type of brinkmanship, which the ABM Treaty
sought to quell. As part of its ratification process for the 2011 New
START arms-control treaty with the U.S., Russia stipulated that
further cuts to its arsenal would require limitations on strategic
defenses. More recently, President Vladimir Putin announced
that Russia is developing several new strategic nuclear delivery
systems that are designed specifically to defeat or evade U.S. mis-
sile defense systems. These include a nuclear-capable hypersonic
weapon that could fly undetected by current sensors and a drone
submarine that could carry nuclear weapons designed to destroy
U.S. coastal cities.
China, for its part, recently added multiple nuclear warheads
to its large ballistic missiles—a change the dod, in its report to
Congress on China’s military power, attributed in part to concerns
about advances in U.S. strategic defenses.
Beyond the potential for missile defense to increase nuclear
threats the U.S. faces is the real possibility that a false sense of se-
curity will distort U.S. decision-making. Misunderstanding the
system’s capability and believing that missile defense is highly ef-
fective or even somewhat effective could lead U.S. leaders to take
more risks in foreign policy. An unfounded faith in missile defense
reduces incentives to pursue political solutions to national securi-ty problems and to improve nuclear arms control. Nuclear-armed
missiles are a political problem that technology cannot solve.HEIGHTENED RISK
although thE modEst sizE of the current GMD system somewhat
limits its destabilizing potential, missile defense proponents are
pushing to expand other U.S. missile defense capabilities. The na-
vy’s Aegis ship-based missile defense system was developed to de-
fend against short- and medium-range missiles in particular re-
gions, but Congress has called for testing a new Aegis interceptor
against an intercontinental-range missile, thus demonstrating its
potential for strategic missile defense. Current plans call for de-
ploying several hundred of these new interceptors on ships over
the next two decades to establish a large, mobile, strategic missile
defense capability that could be used around the world. Such a
system is certain to cause concerns in Russia and China and is
the kind of system the ABM Treaty was intended to stop.
The current defense budget also requests money to begin de-
veloping a space-based missile defense system designed to inter-
cept long-range missiles right after launch, during their boost
phase and before they can deploy countermeasures. These space-
based systems would be enormously expensive yet vulnerable to
attack and therefore ineffective—and highly destabilizing.
As with the decision to proceed with the GMD program, this
missile defense expansion is taking place with very limited dis-
cussion and not enough assessment of the benefits and costs. The
price is high. The total GMD cost is projected to reach at least $67
billion if the Pentagon fields 64 interceptors, according to a 2018
U.S. Government Accountability Office report. An “austere” space-
based interceptor capability would require 650 satellites and cost
upward of $300 billion, says a 2012 National Research Council re-
port. Real resources are being spent on the illusion of a defense.
But there is another, even more important cost: our national
security. Current U.S. missile defense plans are being driven large-
ly by technology, politics and fear. As in the past, this is happening
with insufficient understanding and consideration of the limited
protection these systems can realistically provide. Missile defens-
es will not allow us to escape our vulnerability to nuclear weap-
ons. Instead large-scale deployments will create barriers to taking
real steps toward reducing nuclear risks—by blocking further
cuts in nuclear arsenals and potentially spurring new deploy-
ments. This process of moving blindly and quickly ahead threat-
ens to lead to a world filled with greater threats, not lesser ones.MORE TO EXPLORE
2015 Assessment of the Ballistic Missile Defense System (BMDS). Director,
Operational Test and Evaluation. Department of Defense, April 2016. https://apps.dtic.
mil/dtic/tr/fulltext/u2/1011964.pdf
Shielded from Oversight: The Disastrous US Approach to Strategic Missile Defense.
Laura Grego, George N. Lewis and David Wright. Union of Concerned Scientists, July- http://www.ucsusa.org/nuclear-weapons/us-missile-defense/
shielded-from-oversight
The Warfighter and Decision Makers Would Benefit from Better Communication
about the System’s Capabilities and Limitations. U.S. Government Accountability
Office, May 30, 2018. http://www.gao.gov/products/GAO-18-324
FROM OUR ARCHIVES
The Dynamics of the Arms Race. George W. Rathjens; April 1969.
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