The crisis of nuclear arms control
In late 1969, U.S. and Soviet delegations began the SALT negotiations, which would result in a package deal consisting of two basic documents signed in May 1972: an Interim Agreement on Certain Measures with Respect to the Limitation of Strategic Offensive Arms and a Treaty on the Limitation of Anti-Ballistic Missile Systems, known as the ABM Treaty (Ambrose 2018). For both sides, the Interim Agreement froze the number of fixed land-based intercontinental ballistic missile (ICBM) launchers and put a cap on the number of submarine-launched ballistic missiles (SLBMs) and SLBM-capable submarines held by each party. The ABM Treaty simultaneously aimed to limit a significant technology driver of the arms race: the incipient technical capability to shoot down enemy missiles in flight by means of ballistic missiles, which threatened to undermine strategic stability (Schelling 1985). With the first technical breakthroughs reached under the U.S. Sentinel program in the 1960s, ballistic missile defense became widely discussed as a possible means of achieving strategic invulnerability. Against this background, the ABM Treaty allowed both sides to each deploy a strategic missile defense system with up to 100 interceptor missiles to protect a specific target. Verifying both accords, the sides agreed to rely on their respective National Technical Means (NTMs). In hindsight, the SALT negotiations were significant insofar as they represented the beginning of a process and dealt with the increasingly difficult offense/defense relationship between the parties.
In terms of both sides’ willingness to shield the SALT negotiations from political disruptions, détente had clearly helped to facilitate the process since it had led to an easing of general political tensions. Still, the existence of a shared willingness to shield the arms control process became evident when the U.S. bombing campaign in Vietnam complicated the last stages of the negotiations but did not prevent both parties from reaching an agreement (Ambrose 2018). At the domestic level, Republican President Richard Nixon could build détente on the rather conciliatory policies of his Democratic predecessor when it came to the USSR, thus securing bipartisan domestic support for his arms control policies.