umm, that's 40 years ago you're talking about, and it was Harry Truman who came after, so I say it was sinking gradually since then. In any case voting for warmongers is kind of an approval to them, people have every right to distinguish themselves from warmongers.
I don't really care about labor rights that much in this discussion, but I strongly doubt that you can achieve any by "voting blue, no matter who", you're not really voting here imo, you're just showing the lobbyists that you're accepting anything blue they offer. The example of FDR only shows that your party has been infiltrated and needs a purge of some kind, instead of unconditional support.