Ron Paul or Gary Johnson?

With Gary Johnson's entry into the 2012 presidential race, David Wiegel has an interesting article. The article's subhead presents an interesting conflict for libertarians: with Ron Paul in the race too, who should libertarians support?

In my view, libertarians should support Johnson over Paul for three major reasons:

• Paul's immigration stance. For all of America's bad regulations, perhaps none have a bigger humanitarian cost than immigration restrictions. For example, minimum wage laws might create unemployment. However, the suburban teenager who lost a potential job at McDonald's has lost far less than the Haitian who cannot shine shoes here legally despite suffering from dire poverty and malnutrition abroad. Unfortunately, Paul's record on immigration has been Tancredoesque.
• The perfect is the enemy of the good. As Ilya Somin has noted, Ron Paul has opposed relatively libertarian policies such as free trade agreements and school vouchers. As Somin puts it, "[e]ven if trade agreements and vouchers are not the optimal libertarian policies, they are surely superior to the status quo of tariffs and government monopoly schooling."
• Johnson's main issue vs. Paul's. Realistically, neither Paul nor Johnson can win the Republican nomination. Their primary value in an election is sparking a national debate over certain issues. Ron Paul's main issue is, arguably, monetary policy. And most Americans, myself included, do not care about monetary policy. Johnson, on the other hand, has made marijuana legalization one of his top issues. His focus on the issue in debates might attract young voters to the libertarian movement. After all, "legalize pot" is a far sexier political slogan than "end the Fed."