The declaration of a global war on terror in the aftermath of the attacks of in September 2001 constituted the single most ambitious reordering of America's foreign policy objectives since the Second World War. Alongside this re-evaluation of foreign policy priorities came a stark warning to the rest of the world. At the joint session of the United States Congress following the attacks, President Bush said that 'every nation, in every region, now has a decision to make. Either you are with us, or you are with the terrorists.' This ultimatum deepened America's relations with states that had a strong interest in destroying Al-Qaeda, and strained those with states that had mixed records in combating terrorism, such as Saudi Arabia. While September 11 did not change everything-the unipolar structure of the international system remained intact, for example-it nevertheless profoundly altered American grand strategy, reshuffling the alliance system that had served as the foundation of US foreign policy since 1945 and making the defeat of terrorism the chief object of American power. For a brief time the 'war on terror' appeared to chart a new, even revolutionary, direction for America's grand strategy.