Charlie Crist is getting killed by a hug.

The Republican governor is being bombarded with images of him hugging President Barack Obama when he was in Florida to pitch his $787 billion economic stimulus plan earlier this year.

In just the past two weeks, that hug has appeared in an ad by the conservative Club for Growth attacking Crist, in a Democratic National Committee e-mail highlighting his recent assertion that he actually didn't "endorse" the stimulus bill and in headlines all over Florida, including one Wednesday that read: "Charlie Crist needs to figure out a way to undo a hug."

It will only get worse.

"These kinds of images can be deadly," said Republican strategist Mark McKinnon. "Circumstances and context don't matter. People impose their own meaning and interpretations. And it's impossible to undo."

It is one of the oldest and simplest forms of affection. It's spanned cultures and religions and gone without stigma for generations. In politics, though, it's never that simple. And as people, and politicians, have become more comfortable with the hug - particularly the "man hug" (always with a handshake in between to keep the chests from touching) - a downside of this friendly gesture has emerged.

Crist, who until recently maintained untouchable approval ratings, is now getting a taste of what a string of politicians over the past decade have learned the hard way: You've got to watch whom you hug.

In other words, political PDAs can be career killers.

Sometimes the hug comes and goes (Hillary Clinton and Yasser Arafat's wife). Other times, it becomes such a fixture in a campaign that it indelibly labels a candidate (John McCain and George W. Bush).

The hug is most dangerous when it reinforces a narrative that's already resonating with voters.

Take Crist. It's not only that his Obama hug feeds into the widespread distrust of him among conservative Florida Republicans and allows his U.S. Senate primary opponent, Marco Rubio, to paint him as a liberal. Crist's bipartisan embrace also comes at a time when there is a mounting effort among some in the GOP to drive out Republican candidates who aren't seen as conservative enough.

Democratic strategist Chris Lehane called Crist's bipartisan hug a "twofer."

"This hurts him," he said.

Roger Handberg, a political science professor at the University of Central Florida, put it more starkly: "What's Charlie Crist's hug of Obama going to do for him?" he asked. "Probably get him defeated."

Handberg predicted that Rubio will "beat him to death with the picture."

The hug attack is fairly new. That it exists at all indicates a cultural shift. As Lehane noted, it's hard to imagine John F. Kennedy publicly hugging fellow politicians, as the macho cast of the HBO series "Entourage" does.

Crist has tried to shrug off the hug. "I'm a civil guy," he explained when the gesture started to creep up as an issue.

But civil translates in civics, not in politics, where spontaneous moments of seemingly innocuous public displays of affection can come back to haunt someone.

In the past few election cycles, the hug has done its share of damage.

Ned Lamont was a political novice in 2006 when he ran a successful primary challenge against Sen. Joe Lieberman that was essentially based on the image of the veteran Connecticut Democrat being embraced by President George W. Bush after the 2005 State of the Union address. Bush even appeared to give Lieberman a peck on the cheek.

Lieberman's embrace of the embattled Republican president played into the already-prevailing notion that he was out of touch with his liberal New England constituents.