Stephen Walt enumerates a list of the US's best foreign policy moves, including the Marshall Plan, the Camp David Accords, the opening to China, Bretton Woods, the Non-Proliferation Treaty and German Reunification. It is part of an argument that diplomacy is better than force. Well, yeah, but it often takes two to tango, and diplomacy requires the other side to be willing to bargain. Still, it is a good list that I cannot quibble with, except I might add:
Deciding to intervene in the Korean War. A use of force that kept South Korea from being under the North Koreans. While it took perhaps longer for South Korea to become democratic, the gap between South and North Korea on pretty much every measure is about as vast as it gets. Plus my first car and the next one were both made in South Korea. The huge mistake here was going past the 38th parallel to bring China into it. But it was our first limited war and we didn't really get the whole idea of limits until we got close to the Chinese border. Oh well. At least it provided a dramatic lesson in civilian control of the military.
World War II. Sure, the US was late to the party, but made most of the right decisions once engaged. Well, even before, supporting the UK in ways that were pretty war-like. FDR over-ruled the military who wanted to invade France as fast as possible to get the war over with.
The Berlin Airlift was pretty forceful as well. The US did make a difference when really needed in World War I as well.
Iraq 1991. Bad dipomacy in that we did not send Hussein a clearer signal, but the US did rally heaps of support and then launched a war to kick out the Iraqis. The big regret was not spending a day or two more destroying the Republican Guard, but we had no mandate for Baghdad then, and 2003 revealed that 1991 Dick Cheney was pretty smart about restraint.
Spanish-American War? I have no idea.
I do agree that many of the American uses of force were big-time mistakes: War of 1812, Iraq 2003, Cambodia bombing and invasion, toppling Iran's govt in 1953 (and we could probably throw in a bunch of other coups the US helped along, such as Chile), intervening in the Russian civil war along with the other nervous Europeans, Bay of Pigs, Nicaragua (supporting El Salvador, on the other hand, not so bad in retrospect, although not nirvana either), Drug wars (see Peter Andreas's book)....
Oh, and NATO, if a good thing as Walt suggests, was diplomacy and force--bargaining with countries to improve deterrence in Europe.
Anyhow, the American record is both good and bad. Diplomacy is usually but not always better than the use of force.