(And the comments remind me of why I'm no longer one, with people insisting on the importance of economic libertarianism because "freedom is indivisible." Actually, freedom is divisible at least two ways: The idea that as soon as a state tries to regulate the market in any way, it is on an inevitable path to gulags is, to say, the least, faith-based. Over on the other side, people say, "I can't be free until everyone is." If so, you will never be free, and no one ever has been.)
Of course, many liberals opposed the two wars, but they often had doubts. Maybe we should be interfering in other countries' affairs for their own good; maybe we should be protecting people from those nasty substances they want to abuse themselves with. nellorat has started another fascinating discussion on, among other things, a quote from Valis: "Your problem is that you try to help people."
Helping people can be great, especially if they want to be helped. But helping people for their own good, whether they want it or not, is a recipe for disaster, whether it's Woodrow Wilson and his spiritual heirs trying to inflict democracy on the whole world or the narcs protecting us from the current list of Harmful Substances. Oversimplification: Liberals help people; libertarians don't.
There was a third issue in the 70s where the conservatives, as ever, wanted to control and forbid; the libertarians wanted to leave people alone; and the liberals were divided between leaving alone and helping by protecting people from themselves. I was very strongly on the libertarian side, and I'm glad it is turning to be the winning one in the debate on homosexuality.