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THAAD in South Korea Won’t Defuse Current Tensions

Eric Gomez

Last week
U.S. officials confirmed
that the Terminal High Altitude Area
Defense (THAAD) missile defense battery deployed
on a South Korean golf course
reached initial operating
capability. As tensions grow on the Korean peninsula, THAAD’s
deployment is supposed to improve deterrence by bolstering the
ability of the United States and South Korea to defend against
North Korean ballistic missiles.

While THAAD does reduce the chances of a successful North Korean
missile attack against important U.S. military bases and some South
Korean cities, it probably won’t do much to cool down the situation
on the peninsula. In fact, THAAD could contribute to instability
and increase the likelihood of a crisis.

Why is that? First, it is important to understand what the THAAD
system is and isn’t capable of doing.

THAAD is not able to defend Seoul
from North Korean missiles
because most of the capital city is just outside the 200 km range
of THAAD’s interceptors. While not in a position to defend Seoul,
THAAD could protect several locations that are essential for
conducting sustained combat operations against North Korea, such as
the port of Busan and Kunsan air base. Moreover, even if THAAD were
deployed closer to Seoul, it would not be able to defend against
conventional artillery threat to the city

The Trump administration
will have to find another way out of this crisis.

Critically, THAAD would not be able to shoot
down a North Korean missile test
or an intercontinental
ballistic missile (ICBM) heading for the U.S. homeland. THAAD can
only engage missiles as they fall back down to earth. If a missile
is falling within the engagement range of THAAD’s interceptors,
then North Korea is not testing a missile, it is attacking South

It will not work for U.S. homeland defense, either. The only
thing capable of defending the continental U.S. from ICBMs is the
Midcourse Defense (GMD) system
, which has a spotty testing
record. While THAAD could not shoot down an ICBM, its radar could
provide targeting data to the GMD to improve the chance of a
successful intercept, but that is hardly a guarantee of

With these technical limitations in mind, THAAD’s main purpose
is to provide a protective umbrella for U.S. air force bases in
South Korea, and the port of Busan, the primary port of entry for
follow-on U.S. ground forces in the event of a long-term fight with
North Korea.

But although missile defense systems are usually viewed as
solely defensive, the protection they provide also creates a
perverse incentive for U.S. military planners to use force
offensively. If U.S. planners believe essential military facilities
are relatively safe from missile attack, they could be emboldened
to launch first strikes against North Korea’s nuclear forces.

Currently, the United States, South Korea, and North Korea all
face strong incentives to go first in a conflict. The best way for
the United States and South Korea to limit the damage of a North
Korean attack is to destroy the North’s nuclear weapons on the
ground or
kill Kim Jong Un
before he can give the order. Unfortunately,
this also places Kim Jong Un in a “use
it or lose it
” position to attack first with his nuclear
weapons in the hope of short-circuiting a disarming attack.

Before THAAD, a disarming blow was incredibly risky because of
the damage that just a few surviving nuclear-armed missiles could
do to U.S. forces in South Korea. The risk and danger of a
disarming strike are both still high, but THAAD does reduce them by
providing a better shield against any weapons that may survive the
first strike.

Ultimately, THAAD will do little to defuse the current tensions
on the Korean peninsula. The greater protection it provides to U.S.
troops could make U.S. escalation less costly and therefore more
attractive. The Trump administration will have to find another way
out of this crisis.

Eric Gomez is a policy analyst for defense and foreign policy studies at the Cato Institute.