I'm talking about the leaders of the parties. Different states will behave differently because of cultural differences. California is a hotbed of wokeness because of Hollywood, but that's a special case. The Democratic presidential candidates have been centrists since the 1990s.

Sometimes war might be necessary as a way of averting a greater disaster, such as the growth of an unstable foreign military power. The US might prolong its wars because it fights them in relatively civil ways (unlike, say, Russia).