What is it that happens to politicians when they get in front of rich people — and particularly, rich people to whom they are indebted for contributions?

Mitt Romney’s biggest campaign stumble yet may well be his characterization of nearly half the country as self-pitying, government-dependent slackers “who believe that they are entitled to health care, to food, to housing, to you name it. These are people who pay no income tax.”

But that line, now made public via a video leaked to the liberal magazine Mother Jones, most likely played well with the audience to which Romney delivered it: well-heeled donors at a fundraiser hosted by a private equity manager in Boca Raton, Fla.

Romney now concedes his point was “not elegantly stated.” That is because feeding stereotypes rarely is.

But Romney is far from the first politician to get in hot water for indulging the preconceptions of his rich donors.

In 2008, Barack Obama was at a similar event in liberal San Francisco, when he observed that “bitter” small-town Americans “cling” to their faith, their guns and their “antipathy to people who aren’t like them.”

While it was not a fatal error, that line itself continues to cling to Obama. It remains a staple in Republican stump speeches that goes over well in parts of the country where it comes off as snobby bigotry against white working-class voters.

“Every now and then, President Obama sorta drops his veil. He’s less coy about his philosophy, he sort of reveals his true governing philosophy, what he really believes,” GOP vice presidential nominee Paul Ryan said as he campaigned in Pennsylvania last month. “Hey, I’m a Catholic deer hunter. I am happy to be clinging to my guns and my religion.”

One problem, of course, is that in the era of camera phones and the Internet, there is no such thing as a truly private political event any more. Which means that politicians have to be guarded in their words no matter where they are.

But sometimes, even when there are reporters present, they just can’t stop themselves when an opportunity to pander to their big-money donors presents itself.

In 1995, President Bill Clinton created a furor when he offered a group of well-heeled contributors in Houston this startling confession: “Probably there are people in this room still mad at me at that budget because you think I raised your taxes too much. It might surprise you to know that I think I raised them too much, too.”

His remarks came after his own party had lost control of Congress — with many lawmakers losing their seats, in part, over that tax increase that Clinton had pushed through on a partisan vote.

In those pre-Internet days, the admission got Republican fax machines humming, with GOP leaders employing them as an argument for the very tax cuts that Clinton was resisting at the time.

And Clinton’s allies, who had sacrificed so much, were wounded.

“He doesn’t understand that he’s conceding the principles,” Sen. Daniel Patrick Moynihan (D-N.Y.) told the New York Times. “He’s running for reelection; he’s raising money in Houston.”