The United States is a huge, insular country that spans a continent. But the outside world has nonetheless always played a big role in modern US presidential elections. By tradition, one of the two presidential debates is always devoted to foreign affairs. Foreign policy is likely to loom even larger in the 2008 presidential election than normal. This is for two reasons. First, the Iraq war; second the fact that John McCain, the Republican candidate, sees his greater experience on national security issues as a trump card.
Three particular debates will dominate. On Iraq, the argument will be framed as--'to withdraw or to stay'. When it comes to the wider question of countries placed in President Bush's 'axis of evil', the question will be 'to engage or to shun'. Finally, there is a more intellectual debate to do with how best to reinvigorate American leadership in the world. Mr McCain wants to construct a new Alliance of Democracies; Barack Obama is sceptical. In all three cases, the differences between the candidates are smaller and more nuanced than some of the campaign rhetoric might suggest.
On Iraq, the starting positions of the two candidates sound starkly different. Mr Obama has talked of trying to get all American troops out within sixteen months; Mr McCain has speculated about US troops staying in Iraq for up to one hundred years. Lately, however, the two candidates have begun to moderate their positions. Mr McCain now says that he aspires to get all US troops home by 2013. Mr Obama has acknowledged that--of course--he would have to adjust his policies, in accordance with realities on the ground.
Some cynics suggest that--in reality--the two candidates would end up with pretty similar policies. They would both have to balance the overwhelming public desire to see the end of the Iraq war, with the need to avoid a strategic and humanitarian disaster in Iraq. But that is too simple. An Obama presidency would probably see a much faster withdrawal of US troops than a McCain presidency. Mr Obama's challenge in the campaign will be to persuade voters that this can be done responsibly. Mr McCain will need to offer some realistic prospect that the end of the war is in sight.
Whether or not to talk to enemies is the other great cleavage in the foreign policy debate. Mr Obama has sought to capitalise on American war-weariness--and the feeling that the Bush presidency has been too bellicose and moralistic--by promising to talk 'without preconditions'...