Who are these centrist, independent-minded voters who swung the elections in Virginia, New Jersey and Massachusetts to Republican candidates and are likely to be crucial in races this fall?
Political analysts are searching for a name. They have tried "tea partier," "populist," "conservative," even "strange and unpredictable."
None of these fits, however.
These voters are neither populist nor conservative. But many may be libertarian — fiscally conservative but socially liberal or tolerant.
A careful look at polling data shows these voters may be less mysterious than analysts think.
Libertarians seem to be a leading indicator of this trend in centrist, independent-minded voters, based on an analysis of many years of polling data. We estimate that libertarians compose from 14 percent to 23 percent of voters nationally. They are among the few real swing voters in U.S. politics.
Libertarian voters are often torn between their aversion to the Republicans' social conservatism and the Democrats' fiscal irresponsibility.
These days, they are angry about spending, deficits and government takeovers — but less motivated by social issues. Libertarians are slightly more likely to be male, white, independent and moderate than the general public.
In the past, libertarians often voted Republican as often as 70 percent of the time.
But through the Bush years, Republicans expanded entitlements and spent taxpayers' money faster than Democrats. This gave libertarians less reason to stick with them.
In fact, polls in 2004 and 2006 showed libertarian voters moving toward the Democrats. They may well have cost Republicans control of Congress.
But then, according to our new data, libertarians voted against Barack Obama in 2008. They feared the combination of a Democratic president and a Democratic Congress in a time of financial crisis.
Massachusetts polls confirmed this libertarian shift among independents.
A Washington Post-Kaiser Family Foundation-Harvard University poll found that Scott Brown won 65 percent of independents to Martha Coakley's 34 percent, just 14 months after Obama carried 57 percent of Massachusetts independents.
In addition, 63 percent of 2008 Massachusetts voters agreed that government should do more to solve problems. That number was down to 50 percent in the January special election — with 47 percent saying government is doing too many things better left to businesses and individuals.
Most libertarians voted Republican in 2008. But younger libertarians joined other young voters in supporting Obama.
This had shifted by the special election, however.
A POLITICO/Insider Advantage poll showed Brown leading among voters younger than 30 by 61 percent to 30 percent. In contrast, the 2008 exit poll showed 18-to-29-year-olds in Massachusetts voting for Obama 78 percent to 20 percent.
Though Brown is no libertarian, he made arguments that could appeal to them. Most notably, he campaigned against health care reform and tax increases.
Brown argued that he'd be among the Senate opposition to the current governing agenda. But he played down social issues — his positions on abortion and gay marriage were more moderate than those of most Republicans elsewhere.
Of course, many local issues figured prominently — from corruption on Beacon Hill to his opponent's poor campaign. But in many ways, Brown's campaign copied the winning strategy of Bob McDonnell in the race for Virginia governor — emphasizing fiscal issues and playing down social ones. This would appeal to libertarian voters.
So, if many of these centrist, independent voters are indeed libertarians, why aren't libertarians better recognized?
First, the word "libertarian" is still unfamiliar — even to many who hold "fiscally conservative, socially liberal" views. Pollsters rarely use it.
So in polls, many libertarians call themselves "conservative," "independent" or "moderate" — making it hard for analysts to recognize them.
In states such as Massachusetts, many of these voters likely call themselves Democrats — but don't always vote that way. For example, Massachusetts voters elected Republicans to the governor's mansion for 16 years before Democrat Deval Patrick's election in 2006.
Second, libertarian voters have traditionally been less likely to organize.
In the past three years, however, libertarians have become a more visible, organized force in politics — particularly as campaigns move online. Ron Paul's campaign demonstrated that libertarians can organize and raise large sums of money on the Internet.
Meanwhile, tea party protests showed that libertarian-inspired anger can boil over into spontaneous, nationwide rallies. On Sept. 12, 2009, more than 100,000 people marched on Washington to protest federal spending and the growth of government — many carrying nerdy, libertarian-inspired signs such as "I Am John Galt," referring to the protagonist of Ayn Rand's "Atlas Shrugged."
Libertarians are emerging as a force within U.S. politics. While political leaders such as Sarah Palin and Mike Huckabee and media stars like Glenn Beck and Rush Limbaugh are icons to a "conservative base," it is not yet clear what political leaders might represent these libertarian voters.
But with candidates working to capitalize on voter angst in the 2010 midterms, there are sure to be many politicians angling to lead this libertarian vote.
The 1994 GOP sweep of congressional elections was dubbed the "Republican Revolution."
If Republicans make big gains in 2010 with libertarian votes, we could be hearing about a "libertarian revolution."