And as I allready wrote in only two instances did democracies suffer horrendous casualties.
Again I allready wrote that Britain&France during WWI are one of two exception. As for Britain sustaining "horrendous" casualties during WW2 - thats just not true and as for the British public not blinking I would suggest you read 1940: Myth and reality by Clive Ponting. The British DID blink and wanted the war to end despite relatively low casualties.
Once again I have to say that I allready named this as one of the two exceptions.
You call Peru a democracy with the likes of
Nicolás de Piérola and his sucessors? Thanks for the laugh. Also the conflict was quite low on casualties.
Or when the casualties are to high or expected to be to high or when the war drags on for to long ect I suggest you read the excellent book by Dan Reiter Democracies at War:
https://www.amazon.com/Democracies-at-War-Dan-Reiter/dp/0691089493
Fact is that the US was fighting a two front war and Americans saw Japan as the main enemy. And fact is that the US could easily leave the war in Europe without much consequences. Now explain to the public that you still remain in the war in Europe despite the Soviets beeing crushed and victory so far away that noone can even see it. At a time when Japan was steamrolling the Phillipines and large parts of the Pacific. After checking Japan explain to the people why you waste resources on a lost war in Europe instead of concentrating on Japan. After the victory over Japan explain to the people why they should restart/remain in a conflict that would make the Pacific War look like childs play.
The support of the American people for WW2 was there because for Americans the war brought very little burden and very little casualties. With the Soviets out of the war, the Americans will experience a far greater burden and far greater casualties which will lead to much less support for the war and which will open doors for a negotiated peace. The very notion that Roosevelts little mantra of "Unconditional Surrender" would have been blindly followed by the American people, even after horror reports of how much lives an invasion of Europe would cost,even after mounting casualties and even after a defeat of Japan is simply ludicrous.