Scott Brown’s victory in Massachusetts seems to reflect some of the trends David Kirby and I note in our new study, “The Libertarian Vote in the Age of Obama,” released today. We wrote, “Libertarians seem to be a lead indicator of trends in centrist, independent-minded voters. If libertarians continue to lead the independents away from Obama, Democrats will lose 2010 midterm elections they would otherwise win.” That seems to have happened in Virginia, New Jersey, and now Massachusetts. Young voters, whom we examine in the study, also seem to have moved sharply in Massachusetts from heavy support for Obama in 2008 to slightly less strong support for Brown this week.

Using our strict screen based on American National Election Studies data, we find that 14 percent of voters were libertarian in 2008. Other analysts using broader criteria find larger numbers. Gallup calculates the distribution of ideology every year and found that libertarians made up 23 percent of respondents in their 2009 survey. Our analysis of data from a 2007 Washington Post-ABC News poll found that people with libertarian views were 26 percent of respondents. And a Zogby poll found that 59 percent of Americans would describe themselves as “fiscally conservative and socially liberal,” while 44 percent would accept the description “fiscally conservative and socially liberal, also known as libertarian.”

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, presumably because the prospect of a Democratic president with a Democratic Congress in the midst of a financial crisis was frightening to small-government voters. Also, while many libertarian intellectuals had a real antipathy to McCain, the typical libertarian voter saw McCain as an independent, straight-talking maverick who was a strong opponent of earmarks and pork-barrel spending and never talked about social issues.

One encouraging point in the study: libertarians may be becoming more organized. In our 2006 study we wrote, “Social conservatives have evangelical churches, the Christian Coalition, and Focus on the Family.… Liberals have unions.… Libertarians have think tanks.” In the past three years, however, libertarians have become a more visible, organized force in politics, particularly as campaigns move online. Note the Ron Paul campaign and the heavy libertarian involvement in the widespread and decentralized “Tea Party” movement.

The new study also includes new data on young libertarian voters, Ron Paul voters, libertarians and abortion, “secular centrist” voters, and how libertarians voted for Congress in the past five elections.