17. The ABM Treaty and theatre ballistic missile defence

Summary

For over two decades the Anti-Ballistic Missile (ABM) Treaty has been an
important diplomatic tool for managing the strategic nuclear arms
competition. The Treaty was signed by the USA and the USSR and entered into
force in 1972. Amended in a Protocol in 1974, it is now in force for the USA
and for Russia as the legal successor to the USSR. It obligates them not to
undertake to build a nation-wide defence system against strategic ballistic
missile attack and severely limits the development and deployment of permitted
missile defences. Among other provisions, it prohibits giving air-defence
missiles, radars or launchers the technical capability to counter strategic
ballistic missiles or from testing them in a strategic ABM mode.

Ballistic missile defence (BMD) reappeared on the arms control agenda in 1993:
at issue was the Clinton Administration's proposal to permit the testing and
deployment of new advanced-capability theatre missile defence (TMD), or
anti-tactical ballistic missile (ATBM), systems designed to defend US allies
and US armed forces operating overseas. Critics have argued that these systems
would have significant capabilities to intercept strategic ballistic missiles
and that allowing deployment would create a serious loophole in the ABM
Treaty.

TMD systems are not formally subject to the Treaty, which limits only strategic
ABM systems. However, the threshold between strategic and theatre ballistic
missiles is not technically clear-cut and the characteristics of strategic and
non-strategic defences overlap. In November 1993 the USA initiated discussions
with Russia at the Standing Consultative Commission (SCC) seeking to establish
a demarcation between theatre and strategic missile defence systems based on
demonstrated technical performance parameters. These discussions had stalled
by the end of 1994. The Clinton Administration announced in early 1995 that the
USA would proceed with the testing of a sophisticated new long-range TMD
system, despite objections that doing so would be a violation of the ABM
Treaty.

Both US and Russian advanced-capability TMD programmes and the proposed
allowances in the ABM Treaty seem excessive in comparison to avowed current
threats or hypothetical future threats. Even if agreement is reached in the SCC
on revising the ABM Treaty, the testing and deployment of the systems currently
under development threaten to undermine the integrity of the Treaty as one of
the cornerstones of the post-cold war strategic nuclear balance. They would
reduce the prospects for further nuclear disarmament by the USA and Russia and
compel the other nuclear weapon states to reconsider their strategic force
modernization plans. In addition, they would threaten eventually to weaken the
non-proliferation constraints among the non-nuclear weapon states.

New provisions for more intrusive verification methods and transparency could
ensure ABM Treaty compliance in line with the post-cold war logic of TMD
advocates. The ability of the USA and Russia to cooperate in the development of
theatre anti-missile technologies would be a good test of the validity of their 'strategic partnership'.