Visiting European politicians, officials and journalists are hardly rare sightings in Washington, DC.

Indeed they stream through regularly, at all times of year, to get updates on the latest developments in what used to be called the capital of the free world.

Lately, however, this constant stream has turned into a deluge. Not a day goes by without visitors from Europe offering an expensive lunch to anyone remotely in a position to tell them who is advising whom, to analyse the latest primary results, to speculate on the next ones, or to predict the policies of the likely party nominees. (The truth, of course, is that most of us know little if anything more than our visitors do about these things, but that rarely stops us from accepting an always pleasant lunch.) 

Europe’s interest in the upcoming American election is well warranted, and not only because of the drama of close races or the historic nature of some of the main candidates. It is well warranted because Europeans realise that whereas they have no vote, the outcome of the US election could in some ways impact them nearly as much as it does Americans themselves.

As a visiting Italian member of the European Parliament recently told Roger Cohen of The New York Times, “We’ve learned that a good or bad US president can make the difference between war and peace. A good or bad Italian prime minister makes no difference at all.” 

I won’t touch the notion that an Italian prime minister makes no difference at all (though I could point out that at the time of writing Italy doesn’t actually have a prime minister). But it is impossible to disagree with the first point. While many analysts and scholars often suggest that US foreign policy is determined primarily by “structural” factors, “objective” interests, or an “enduring” strategic culture, the reality is that individuals – sometimes elected narrowly and for the most capricious of reasons – can have an enormous impact on the lives of people all over the world. Does anyone doubt that US foreign policy over the past eight years would have been very different had Ralph Nader’s presence on the ballot in the state of Florida not cost Al Gore the 2000 election leaving it to George W Bush to manage what would become the “war on terror”?  

Will the 2008 election matter as much as 2000? All signs are that it very well could, regardless of whether Barack Obama or Hillary Clinton end up winning what is currently a very close Democratic race to face the likely Republican nominee, John McCain.

While widely and rightly seen as a maverick for his willingness to buck the Republican mainstream on issues like campaign finance reform, immigration and gay marriage, on foreign policy McCain would represent far more continuity with the Bush administration than either of his democratic rivals. Even allowing for the fact that each side is playing for its party’s base during primary season and could move toward the centre f......