The original plan for SDI offered nothing specific to the Allies. How, then, should they react? One response, which came to prominence in late 1985, was for a programme to provide SDI-type capabilities for Western Europe: a European Defence Initiative (EDI). More detailed and less ambitious proposals for Anti-Tactical Ballistic Missiles (ATBMs) and Extended Air Defense (EAD) also won considerable support. As these ideas gathered momentum in early 1986, it looked as if NATO might embark on a major new programme to parallel SDI. In examining European responses to SDI – including EDI, ATBMs and EAD – this chapter seeks also to explore and illuminate the course of SDI. The EDI subplot reflects and refracts the themes of the main history.

The immediate reaction in Western Europe to Reagan's speech of 23 March 1983 was one of surprise, falling short of consternation. Many suspected it was an electoral ploy or a passing presidential whim. The West German Defence Minister, Manfred Worner, later the main proponent of EDI, dismissed SDI at the time as ‘absolute Zukunfts-musik’: pie in the sky. Only after the reports of the SDI ‘advisory panels’ and Reagan's re-election (November 1984), when it became clear that BMD was going to remain a major policy issue, was there some deep alarm.

The President had not consulted with the Allies about the ramifications for East–West relations and arms control.