I wish I'd come up with the following myself, but the following quotation is an excerpt from Andrew Sullivan, in the Atlantic Monthly--the full article is well worth reading:
"Consider this hypothetical. It’s November 2008. A young Pakistani Muslim is watching television and sees that this man—Barack Hussein Obama—is the new face of America. In one simple image, America’s soft power has been ratcheted up not a notch, but a logarithm. A brown-skinned man whose father was an African, who grew up in Indonesia and Hawaii, who attended a majority-Muslim school as a boy, is now the alleged enemy. If you wanted the crudest but most effective weapon against the demonization of America that fuels Islamist ideology, Obama’s face gets close. It proves them wrong about what America is in ways no words can."
Andrew Sullivan, "Goodbye to All That," in The Atlantic Monthly, December 2007. http://www.theatlantic.com/doc/200712/obama.
I hadn't really considered the international implications of the primaries, but this guy just hit the nail on the head. Even the first female candidate incarnates "politics as usual," both at home and abroad, at a time when the credibility of the country demands a sharp contrast between the last administration and the next.