Libertarians are probably the weakest leg of the Republican coalition. The religious right and the neocons are much stronger, the former has little reason to oppose this, the latter might be naturally inclined to support it.

Interestingly, I've been hearing a bit about Democratic-leaning "civil libertarians" -- people who want small government without buying into any of the Republican social agenda. Maybe there's a way to build a coalition that can take a big enough bite out of both parties to force them to take notice...