It will be a long, hard road for the United States to get back to a position of trust with even its international allies given not just the disaster that is Bush II, but several presidencies before it.
It was suggested within the Kucinich thread that any Democrat would improve relations with the U.S.'s international allies (presumably meaning the Western democracies and other highly developed democracies like Japan) merely by not being closely tied to Bush.
I would beg to differ. Too may years of stone-faced uncooperation from the U.S. has made all of us in the rest of the world entirely too skeptical of any U.S. administration.
It's going to take a lot more than just not being Bush to win back the U.S.'s former allies in the Western Bloc. Support for the U.S. in general has been plummeting since the 1980s thanks to a series of presidents who have been, from the position of the political mainstream in these countries, completely unpalatable both on foreign policy and on issues of international cooperation. Clinton was, in general, not an exception although he earned significant brownie points over Yugoslavia and generally by the end of his term had restored a small amount of trust on the military/security side.
However, on the non-military aspects of foreign relations, the U.S. is still considered the absolute pits. I think in general (in circles like trade, the environment, and international cooperation) the consensus is that the U.S.'s word isn't worth a fiat dollar, on any subject, and that goes whether a Democrat or a Republican is the one flapping his gums behind the podium. Not even Conservatives in this country (Canada), who are essentially a branch plant of the Republican Party, take the U.S. seriously at all on crucial matters like trade or border security. (Matters crucial not just to Canada, but to the U.S. - Canada is the U.S.'s largest trading partner).
(When I say "political mainstream" in the liberal democracies of the West, that's approximately equivalent to the mainstream left as it would be in the U.S.)
We (and I see this in mainstream opinion in Europe, and the other "middle powers", as much as in Canada) are not going to coming back to some Democratic president with open arms just because they claim to have some magic fairies plan to pull U.S. troops out of Iraq. It's going to take serious coalition-building, serious fence-mending, and a serious willingness to do the work that's been pissed away over much of the last decade as the U.S. have tried to throw roadblocks in the way of every major international initiative I can think of.
In short, before you guys get anyone else to play along, you're going to have to elect an Administration that is serious about being a team player and a principled negotiator, and not picking up their ball and going home in a huff every time something happens or someone says something that they don't like. We haven't seen anyone in the White House like that for a long time, certainly not since Ronald Reagan. And I have to say, from what I see of the candidate roster, there aren't many in the race who can be taken seriously by the world on international issues. Certainly not the three perceived front-runners.
The U.S. is the ten-ton elephant in world affairs. You can get a lot done just by stamping your feet. But ultimately, if the U.S. wants to accomplish much more than just scaring what it wants out of other countries (or buying, like in China) then it's going to have to return to honesty. Which has never seemed further off.