I should also mention the Democrats’ judicial nominations:
Justices Kennedy and Scalia are in their late 70s, and both are the critical fifth vote on tremendously important libertarian principles:
There are four justices on the Supreme Court ready to hold that the First Amendment does not bar Congress from regulating political speech against incumbents.
There are four justices on the Supreme Court ready to hold that the Second Amendment does not create any individual rights against the government.
There are four justices on the Supreme Court ready to hold that the Commerce Clause creates no constraint on Congress’s regulatory powers.
There are likely at least four justices on the Supreme Court ready to hold that the government can choose to discriminate on the basis of race if “diversity” is at issue. [Actually, I think there are four votes willing to allow the government to use race for all sorts of purposes.]
One can point to individual unhappy results from Republican-appointed justices, but it is a mathematical certainty that Obama-appointed justices will flip the Court on these critical issues of the rights of individuals against the government—none more critical than First Amendment protection for political speech. Once that falls, the game is over and libertarians have lost permanently. This alone is a dispositive libertarian case for Romney, even before one gets to the difference between a Romney and Obama on economic freedom and regulation.
I should also mention the Democrats’ judicial nominations:
http://www.volokh.com/2012/10/02/ted-frank-the-single-issue-libertarian-case-for-romney/