From Andrew Bacevich's article in The American Conservative:
An alternative reading of our recent military past might suggest the following: first, that the political utility of forcethe range of political problems where force possesses real relevanceis actually quite narrow; second, that definitive victory of the sort that yields a formal surrender ceremony at Appomattox or on the deck of an American warship tends to be a rarity; third, that ambiguous outcomes are much more probable, with those achieved at a cost far greater than even the most conscientious war planner is likely to anticipate; and fourth, that the prudent statesman therefore turns to force only as a last resort and only when the most vital national interests are at stake. Contra Kristol, force is an “instrument” in the same sense that a slot machine or a roulette wheel qualifies as an instrument.
John Quiggin follows up:
[T]he US faith in force reflects a long history of aversion to foreign wars, going back to the Founders. The US had its share of bellicose nationalists, but compared to nearly all previous states, where success in war was taken as the primary measure of greatness, the US in the 19th century stands out for its pacific nature. But on the relatively rare occasions when the US went to war, it usually did so under (perceived and sometimes actual) conditions of necessity and with the unqualified commitment that entailed.