One of the great ironies of George W. Bush's second term as president is that the two American political parties have flipped positions completely on the question of how extensively to interpret US interests in the world. The Republicans have in effect endorsed humanitarian intervention and open-ended democracy promotion, while the Democrats have become the party of pragmatic caution and focus on national security, narrowly defined. How this reversal occurred is a matter of accident, and the question for the future will be whether their new positions will persist once the nation is past its preoccupation with Iraq.

During the 1990s, many Republicans groused that the Clinton administration used force only in situations where vital US national security interests were not involved. Bill Clinton began his term by expanding the goals of the Somali intervention from disaster relief to nation-building prior to the incident in which 18 army rangers were killed and the US withdrew; he sent US troops to Haiti; and he used US airpower and diplomacy to broker the Dayton accord in Bosnia, and led a Nato coalition to protect the Kosovars from Serb aggression. In response, Condoleezza Rice, while still advising Mr Bush as a candidate in the 2000 presidential campaign, complained that "US forces should not be used to protect schoolchildren", as they were in the Balkans. Mr Bush himself famously remarked: "I don't think our troops ought to be used for what's called nation-building. I think our troops ought to be used to fight and win war."