Leaders of Nato gathering in Bucharest this week face a momentous decision: whether, in the face of fierce Russian opposition, to move Ukraine and Georgia closer towards membership of the alliance. At issue is whether to offer the two countries so-called membership action plans, the recognised final step before becoming an ally.

This question is of enormous geo-strategic importance and has divided the alliance right down the middle. The US strongly favours extending the invitation, hoping it could burnish George W. Bush’s tarnished legacy. It is supported by Nato’s newer members in eastern and central Europe. Meanwhile, much of western Europe, led by Germany, opposes making the offer.