This work analyses the vulnerability of America's land-based missile force to a pre-emptive Soviet strike as an issue in US strategic and political debate. It examines why the issue rose to prominence in the way it did in the 1970s and then fell away as a concern in the 1980s without being solved in the way it had been presented. It details the way in which the issue was exploited for political and strategic purposes which were often at odds with a concern for this vulnerability.