At a time when the United States's position and role in the world is coming under multiple strains and questionings at home and abroad, its citizens are responding to them strongly in this year's election campaigns.
These promise to be the most defining for many years, both for Americans and the world at large. As the primaries draw to a conclusion they have already effectively merged into the presidential elections proper. Barring disasters or miracles John McCain will be the Republican candidate. For the Democrats the contest between Barack Obama and Hillary Clinton is tantalisingly close and now crucially polarised between alternative styles of leadership and demographic appeal.
That there is so much international interest in this US campaign should not surprise. It has a real drama of personality, policy and competitive edge as well as a compelling new public engagement, especially on the Democratic side. All of these readily communicate themselves beyond American shores. And either way the result will make a real difference to a world that is highly exposed to American influence politically, economically and culturally. This point is not diminished if one believes US power is declining, since the management of any such process - whether by greater military posturing, more multilateralism or more economic protectionism - will still have a definite impact.
Prudent observers know, too, that US society is capable of being mobilised politically with a message of hope and potential achievement by creative leadership. That is what voters are looking for amid such uncertainty. If they succeed in finding the right person, Americans can respond in unanticipated ways that could change their domestic performance and world perception. Certainly that is what is needed after the sharp decline in international approval of US policies during the Bush years. Many political leaderships around the world are awaiting the November results impatiently to see whether such a change might be forthcoming - and there will be much good will to be drawn upon by the new presidential team if that is the case. If change does not materialise expectations at home and abroad will be sharply disappointed, with quite unpredictable consequences.
Seen against this international backdrop the candidates present sharply contrasting policies but also several converging themes. Mr McCain is certainly a foreign policy hawk who wants to protect and project US power; but he is also a realist much more at home with the international foreign policy establishment than the Bush neoconservatives were. Mrs Clinton's need to compete with the Republicans on national security reduces her foreign policy leeway, but should not disguise her greater commitment to multilateralism. Mr Obama is the most radical of the three, calling for war resources to be turned over into greater social spending. None of them is likely to shift the basic thrust of US foreign policy and its interests, but there is ample scope for variation.