it would have been longer and more sloppy to end war in Europe without the yanks taking to the dance floor late as usual They were late to both parties because they didn't have large standing armies, preferring to rely on the Bristish Empire spending it's resources as the world police.
They were gifted British designs on warships and planes for manufacture because they didn't have the critical mass of nous to do their own engineering then set about profiting of them as part of the Lend Lease pact....which led to the Silent Gen forever miffed at the US partying through the fifties at the expense of Europe's misery.
