The evolution in the international system from bipolarity to unipolarity has led to shifting patterns of alliances in world politics. Since 9/11, the United States has demonstrated a willingness to use its overwhelming military power to deal with potential or real threats. Contrary to its policy of embedded power in the economic and security institutions of the post-1945 period, the United States increasingly views the multilateral order as an unreasonable restraint on the exercise of hegemonic power. What does this new context mean for Britain? Going back to 1997, the first New Labour government added an internationalist dimension to the traditional roles of acting as a loyal ally to the United States and serving as a bridge across the transatlantic divide. The Iraq war of 2003 showed that the bridge could not bear the weight of the disagreement between 'Old Europe' and the new conservatives in Washington. The Prime Minister's decision to be there 'when the shooting starts' shows that Britain continues to place the bilateral connection with the United States above all other obligations. This article questions whether the Atlanticist identity that underpins the strategic rationale for the special relationship is likely to succeed in delivering the interests and goals set out in the recent UK security strategy document.