Big is out.

Big Oil. Big Government. Big Media. Put “Big” (the capitalization is key) in front of just about anything these days in politics and you can be certain that voters aren’t going to like it.

We are in a populist time when distrust of institutions — banks, Congress — is at an all-time high and the chasm between the haves and the have-nots is growing wider. People believe the system is rigged — and they are angry.

“A common thread that reflects this populism is the anger at out-of-control big government echoed by the tea party and the anger at out-of-control big business echoed by the Occupy movement,” said Dave Beattie, a Democratic pollster. “The commonality of ‘anti-big’ ties both together.”

Channeling that populist ire is a political gold mine in 2012. Need evidence? The rise of former Pennsylvania senator Rick Santorum was built, in no small part, on a populist economic pitch centered on his upbringing in western Pennsylvania.

Santorum’s miner grandfather shtick has been the best stump material of the year,” said Rob Stutzman, a California-based Republican consultant.

And yet, the two candidates likely to face off in the general election are decidedly awkward vessels for the sort of David-vs.-Goliath populism that the country is feeling.

While President Obama’s personal story should have some appeal for voters looking for someone who understands their problems, he’s never worn the cloak of populism easily or well. Obama is, at heart, a college professor in his approach to politics — clinically, not emotionally, studying all sides of an issue. It’s no accident that when Obama is at his best, he’s personalizing his politics. His speech at the memorial service for victims of the Tucson shooting rampage and his remarks regarding Georgetown Law student Sandra Fluke, who was verbally attacked by Rush Limbaugh, are two good examples.

Former Massachusetts governor Mitt Romney is the furthest thing from a populist the GOP could pick in this nomination process. Romney’s background (his father served as governor of Michigan), his personal wealth and his overall demeanor (businessman through and through) scream whatever the opposite of populism is.

(Imagine, for a moment if former Arkansas governor Mike Huckabee ran for president in 2012. Huckabee, marinated in the tradition of Southern populism, would have been a remarkably good fit for the Republican primary electorate. Just saying.)

Polling suggests that Obama starts with an edge over Romney when it comes to understanding the problems of average Americans — the closest measure we have to judge a politician’s populist connectivity.

In a New York Times/CBS survey conducted last month, 55 percent of registered voters — including more than half of electorally critical independents — said that Obama understood their “needs” and “problems.” Just 31 percent said the same of Romney, the lowest of any of the four candidates remaining in the GOP presidential race. (Santorum led the Republican field with 40 percent saying he understood their needs and problems.)

The challenge before Obama and especially Romney is to find ways to play into the populist sentiment coursing through the country, without appearing inauthentic. (The only thing worse than a politician who doesn’t understand “the little guy” is a politician who fakes like he understands the little guy.)

Beattie said his party needs “to continue to make the election broadly about protecting and expanding the middle class.”

“Many voters are angry that a handful of big companies and wealthy individuals seem to get special treatment or get bailed out while they struggle to get by,” Beattie said.

Obama and his campaign team are following that advice. Ads launched in swing states last week attack Romney for siding with “Big Oil” — “Mitt Romney stood with Big Oil . . . for their tax breaks . . . attacking higher mileage standards and renewables,” says the ad’s narrator.

The populist problem is more acute for Romney and, therefore, harder to solve.

Ed Goeas, a Republican pollster, argued that Romney needs to show that Democratic solutions “are ideologically driven and our solutions are driven by results that will make voters’ lives better.” He added that Obama has more work to do on this front than Democrats like to believe. “Obama is working from the weaker position initially, because he originally touched those emotions with many voters and then lost that connection,” Goeas said.

Dave Carney, who served as a senior adviser to Texas Gov. Rick Perry’s presidential campaign, is even more blunt about the contrast Romney needs to draw with Obama on matters of populism. Voters “want a leader who does not want farm dust to be regulated by the [Environmental Protection Agency] or one that does not wish gas were priced even higher at the pump,” he said.

Neither Obama nor Romney is a natural populist. But both men will need to dig deep and find ways to connect with the anger and frustration of the electorate if they want to win. The 2012 election is a populist’s paradise.