Rick Santorum had a somewhat super Tuesday on February 7th. He won all three Republican presidential primaries, thereby reviving a campaign that had failed to follow up on his victory in Iowa. Santorum could become the sole alternative to Romney for the Republican nomination. If that happens, he could become the GOP nominee in 2012. Should libertarians vote for him?

Here’s my (broad) definition of a libertarian. A libertarian cares about individual liberty and thus limited government. Those concerns lead to further commitments to free markets in economics, moral pluralism in culture, and realism and restraint in foreign policy. Government provides a legal order in which individuals pursue their vision of the good life. Politics is more about living together at peace than about making people virtuous.

By his own account, Santorum is anti-libertarian, describing the philosophy as “radical individualism” and a source of cultural decay. He opposes moral pluralism in favor of a society and government that recognizes and acts on Christian virtues. Santorum speaks of free markets, but his cultural commitments are bound to require limits on economic liberty. He also indulges in an economic populism that implies protectionist policies that favor the manufacturing sector. Like many Republicans these days, Santorum also seeks salvation for the Middle East through American military power.

So will libertarians support Obama in the fall? Not necessarily. They will be able to vote for former New Mexico governor Gary Johnson, the likely candidate of the Libertarian Party. He offers an easy way around choosing between the president and Rick Santorum.

Maybe not. Let’s stipulate that Johnson cannot win. If libertarians vote for him, and not their second choice (either Obama or Santorum), they might cause the election of their third choice (Obama or Santorum). Hence we come to the question of the lesser evil.

Is Obama a correct second choice for libertarians? The president is similar to the former senator in one way: both see government as pursuing a moral crusade on behalf of some value. Like generations of progressives, Obama wishes to remake American society in pursuit of “social justice,” not Christian morality. As Friedrich Hayek understood, Obama’s search for “social justice” necessarily abridges economic liberty. Obama’s Libya mission shows that his administration shares George W. Bush’s disdain for realism in foreign policy.

As they say in sports, it’s enough to make you wish they both could lose. But they can’t.

Here’s my libertarian case for Rick Santorum’s nomination (though not his election). Since the early 1990s, Christian conservatives have formed an ever larger portion of the GOP. In Santorum, they would have what they have long sought: a candidate embodying their commitments to a politics of faith. Neoconservatives would also have a candidate committed to transforming the world through foreign policy and military action. The Obama-Santorum race would be more than just a struggle for power between two men. It would be a referendum on ideas and policies that have dominated the GOP for more than decade.

One recent poll has the former senator running even with Obama, but most polls have shown a decided gap of about eight points between the incumbent and Santorum. Right now the latter is not well-known to most voters. As Santorum becomes better known, he might close the gap with Obama. More likely, I think he would drive more secular and independent voters away from the GOP ticket. A ten-point Republican loss in a year when economic weakness suggested a close race would be a political disaster not just for the candidate and his party but also for the ideas they embody. Rick Santorum could be the George McGovern of his party.

Such a disaster might open the door for a different kind of GOP along lines indicated earlier, a party of free markets, moral pluralism, and realism in foreign affairs. Ron Paul has taken some steps this year toward creating such a party. He has attracted votes and inspired activism. His son or another candidate might take up the cause in 2016 and build on Paul’s achievements. Fanciful thinking? Perhaps, but it may take an electoral disaster to free the GOP from the ideas and forces that Rick Santorum represents.

John Samples is director of the Center for Representative Government at the Cato Institute and the author of The Struggle to Limit Government.