For the second part of this ongoing series, I'd like to look at the second half of the title, "the American Way of War". Without doubt, all foreign wars in the history of the United States between 1783 and 1917 generated serious opposition among Americans. You don't have to look hard:
War of 1812: The Hartford Convention threatens the secession of the New England states.
Mexican-American War: This fellow made a name for himself as an opponent of the war, but he represented the views of a couple more key party associates. See documents 1 and 10 here.
Spanish-American War: Support for this relatively popular war demanded Congressional legislation that formally renounced any intention to annex Cuba. The war might have proved less popular without it. The legacy of the war, the annexation of the Philippines, was a different matter.
Even after 1918, the only near-universally supported foreign wars are the Second World War and the Korean War. (Although I wonder if the latter had lasted one more year whether serious opposition to it might have arisen. There's a sort of four-year rule related to American involvement in war.)