In 2006, the Cato Institute's David Boaz and David Kirby crunched some numbers in the service of finding out more about the elusive Libertarian Vote and its role in American politics. Now, they have updated their work, tracking The Libertarian Vote in the Age of Obama. Here's what they found:

Libertarians are about 14 percent of the electorate. Libertarian voters swung away from Bush and the GOP in 2004 and 2006, but in 2008 they swung back, voting for McCain by 71 to 27 percent. Younger libertarians voted 59 percent for Obama versus 36 percent for McCain. But their enthusiasm for his policies may be short-lived. Younger Americans are an optimistic generation, but easily shaken when things go badly. If unemployment continues to remain weak, an economic issue that disproportionately affects young people, this generation of voters could quickly become disillusioned with Obama's policies. Before the 2006 elections, we predicted that if the swing away from the Republicans continued, "Republicans will lose elections they would otherwise win." Now we offer the reverse prediction: if libertarians continue to lead the independents away from Obama, Democrats will lose 2010 midterm elections they would otherwise win.

Boaz and Kirby write about it—but Massachusetts senator-elect Scott Brown is living it.

For those interested in the study's definition of libertarian, here are the details. Snagging results from a respected long standing public option poll series, the study uses three questions to mark someone out as a libertarian: