The Iraq crisis caused a deep rift in US–European relations and within Europe. NATO seemed sure at least to be damaged, if not fatally undermined. But to the dismay of those who have been waiting for many years for NATO finally to unravel, the Atlantic alliance spent 2003 proudly showing off its transformation project, and looking forward to its next enlargement in 2004. Yet these necessary improvements to NATO's political and military structures, and to its deployable capability, cannot alone secure the alliance's future. This article argues that what is needed, as ever, is a shared determination among governments that NATO can continue to serve their needs. There has been no better opportunity since the end of the Cold War to place the US-European security relationship on a firm footing through NATO. There has also been no moment when the penalties of failure have been higher. If NATO's transformation agenda, together with the NATO–EU ‘Berlin Plus’ arrangement, are not exploited to the full, then US-European security relations are unlikely to recover from Iraq.