Could the centrists and independents who turned against George W. Bush and the GOP in the last two elections now be turning away from Barack Obama and the Democrats? Polls offer some hints.

When Gallup recently asked voters to describe themselves politically, 40 percent of Americans describe their views as conservative, 35 percent as moderate, and 21 percent as liberal — a recent shift in the conservative direction.

See the Gallup report here.

But in a 2006 Zogby Poll, 59 percent of voters said they would describe themselves as “fiscally conservative and socially liberal.” They don’t fit comfortably into either party’s base. Many of these are the independents who should rightly be the hot cheerleaders of the electorate, extravagantly courted by both parties. [Disclosure: Cato paid for this question, but the poll itself was Zogby’s regular Thursday-after-the-election poll of people who said they voted.]

Meanwhile, the Pew Research Center found that the much-discussed, much-pandered-to “bases” of the two parties accounted for only about a quarter of the electorate: 11 percent of Americans describe themselves as liberal Democrats, 15 percent conservative Republicans. Independents grew from 30 to 39 percent of the electorate in just five months after the 2008 election.

See the Pew report here.

Libertarian — or fiscally conservative, socially liberal — voters are often torn between their aversions to the Republicans’ social conservatism (and, for some of them, military adventurism) and the Democrats’ fiscal irresponsibility. Usually they end up voting on the basis of economics.

Research that David Kirby and I have done shows that libertarian-leaning voters have typically given up to 70 percent of their votes to Republicans. But in 2004 and 2006, that number fell off sharply. Republican congressional candidates barely held a majority of libertarian votes in 2006, and of course the Republicans took a pounding in that election.

Why did those voters turn away from the Republicans? Well, Bush and the Republican Congress stuck to their social-conservative guns: they sought to ban gay marriage, limit stem cell research, and insert the federal government into Terry Schiavo’s hospital room.

They got bogged down in an unnecessary and endless war, and they asserted extraordinary powers of surveillance and arrest. Meanwhile, they managed to add more than a trillion dollars to the federal budget and launched the biggest new entitlement since Lyndon Johnson’s Great Society. So those who had been willing to accept some social conservatism as the price of fiscal responsibility realized they’d made a bad bargain.

Some of those independents voted Democratic in 2006 and 2008, figuring that the Democrats would be more tolerant and could hardly be more profligate. And what are they now seeing?

President Obama is exceeding all their fears on fiscal and economic issues. After promising a “net spending cut” during the campaign and denouncing “the most fiscally irresponsible administration in history,” he has sent federal spending and the deficit soaring into the stratosphere.

Meanwhile, he’s not delivering what some of his voters hoped for on social issues. No gay marriage, even as Bill Clinton, Dick Cheney, conservative superlawyer Ted Olson, and the legislature of crusty New Hampshire sign on.

No end to the drug war, even though he’s the third president in a row to have acknowledged using drugs. He even mocked a question about drug legalization at his online town hall. (“Dude, we elected that guy, what’s up with that?” is Reason editor Matt Welch’s summary of the blogosphere’s reaction.) No pullout from Iraq.

So once again fiscally conservative, socially liberal voters are starting to wonder if they made a bad bargain.

Independents who turned against the Republicans are likely to become equally disillusioned with Obama, and there’s already some evidence of that in the polls. Support for “smaller government with fewer services” has risen in the ABC News/​Washington Post poll, and independents prefer it by 61 to 35 percent, a margin three times as large as a year ago. The number of people who see Obama as an “old-style tax and spend Democrat” has risen by 11 percentage points.

In a USA Today poll, a majority oppose Obama’s health care efforts and 59 percent say he’s spending too much. In another ABC/Washington Post poll, only 25 percent “strongly approve” of his health care plans, and 33 percent strongly disapprove. His honeymoon may turn out to be as passionate, yet brief, as Britney Spears’ Las Vegas marriage.

It’s hard out here for a fiscally conservative, socially liberal voter. But at least there’s always the other party to try again.