"thorough defeat [of Germany] was under a Dem president, which I think is rather hard to explain"
Maybe not so hard if you accept the notion that the Republican party of today IS the Democratic party of pre-1970. JFK's 'ask not' is a mantra for small government and individual responsibility. The Democratic party of today is a Labor party.
I suppose under that scenario, the only real conservatives of today are the paleos, ala, Barry Goldwater and Ron Paul, which leans into the realm of libertarianism... But that's just speculation.
Actually, another poster made a very good point, which was that the Dems and the left really rallied behind the war against Hitler only after Hitler attacked Stalin, and that to them, a lot of WWII was about supporting Russia.
But I think that what you say about the evolution of the two parties is correct, although I'm not sure the libertarian-leaning wing is representative of a realistic conservative party. That is, libertarians are essentially into the dissolution of all government, which while it may sound great on paper, simply doesn't work. A friend of mine, referring to anarchists (the left-wing version of the curve represented on the right by libertarians), "anarchy is the government of Heaven." In other words, only a society where everyone is already good and already subject to a divine law that they have internalized can run as an anarchist/libertarian society. And of course, since that's not going to happen anytime here on earth and most people have had enough experience of themselves and their neighbors to know this, I guess it's no wonder that these candidates don't reap a lot of votes...