Th contrast is interesting but looking from outside my impression is that american libertarians can afford to be principled on being anti war or in favor of drug liberalization because the coalition they are a part of is willing to give them everything else they want. A libertarian in congress voting against the war agenda is irrelevant, both to wether wars actually happen and to their own agenda. They don't need to sacrifice anything to get republicans to vote against worker's rights or anything else in the libertarian playbook. It's a stark contrast with the democratic party, where you have to play ball to get denied the bare minimum of social policy.