I think David is absolutely correct in his post below that judicial appointments are a big issue for most libertarian-leaning law professors, and on this issue Republican presidents (and their judicial nominees) have done far more to advance libertarian legal views than Democratic presidents. I would add two points to David’s analysis. First, even on those issues where libertarians are more “liberal,” Democratic nominees have not been clearly superior to Republican ones. The most speech protective justice on the Court is Anthony Kennedy. The least speech protective is likely Justice Breyer. On criminal justice issues, the formalism of some conservative justices often leads the to embrace pro-criminal defendant holdings, as we’ve seen in Fourth and Sixth Amendment cases. In this regard, a Justice Scalia or Thomas is often more “libertarian” than a Justice Breyer. There are no paragons of a libertarian jurisprudence on the Court, but in the past thirty years Republican nominees have come far closer than Democratic nominees.
While judicial nominations may overshadow many other issues for libertarian law professors, I think there’s another factor at work. Recent Democratic presidents have tended to be quite disappointing on those issues where libertarians have “liberal” views. Many libertarians had high hopes for President Obama, but he has disappointed them on a range of issues, such as executive power, civil liberties, foreign adventurism, government transparency, drone strikes, and the drug war. He has expanded and entrenched many Bush Administration War on Terror initiatives and has also been disappointing in areas President Clinton was a pleasant surprise, such as trade and the federal budget. Even where I support the President’s policy preferences, as with gay marriage, the administration has been disingenuous.
Reasonable libertarians may disagree as to whether any of this justifies supporting Mitt Romney (as opposed to supporting Gary Johnson or staying home), but I think it is particularly difficult to make a libertarian case for reelecting Obama.