LAS VEGAS — "I love humor," Mitt Romney told CNN in December. If so, he has a funny way of showing it. "Funny" as in, not really that funny. Still, give the former Massachusetts governor his due: He might just be the funniest presidential candidate from that state since John Kerry, or maybe even Michael Dukakis. Call it something to build on.

"She's the best, and it's all downhill from here," Romney said of his wife, Ann, who introduced him at a rally here Wednesday night not far — but galaxies removed — from the comedy hub of the Vegas Strip. He was speaking at a janitorial supply company, with large boxes of toilet paper piled high on shelves next to the stage. Great visual.

In Minnesota last Wednesday, a protester showered Romney with glitter, or "confetti," as he spun it. It covered his hair. "That's not all that's in my hair, I'll tell you that," Romney said. "I glue it on every morning, whether I need to or not."

He loves humor! Like that time in New Hampshire when Romney pretended that a waitress posing for a photo with him had grabbed his tush. "Oh, my goodness gracious," he said, lurching forward. Or in Dubuque, Iowa, when he recalled that Ann had fallen during a visit there. "She said, 'Well, I fell on de butt in Dubuque.' "

Oh, my goodness gracious. This is not to pick on Romney. He is running for a serious job. And he is merely the front-runner in a Republican field that few would carve into any Mount Rushmore of (intentionally) funny politicians.

Newt Gingrich is much better at attracting Laffers (the conservative economist, Arthur) than laughter. Rick Santorum often looks as if he has a headache. Both Gingrich's and Santorum's laugh lines tend more to the caustic than the funny.

"As many of you know, I study history," Gingrich said, helpfully, at a debate. "And unlike the president, I study American history."

Ron Paul has gotten off some of the best quips in debates, but his overriding mood is of a cranky, "get the hell off my lawn" neighbor.

They have all had their moments: the old reliable Dick Cheney hunting joke (Gingrich in a debate), or the "Obama uses a teleprompter a lot" joke (Gingrich, constantly), or an easy Joe Biden crack (Santorum in a speech). Or Paul (at a Florida debate) saying: "I don't think we should go to the moon. I think we maybe should send some politicians up there."

But there are no laugh-riots in this group — no Bob Doles or John McCains, two of the funnier candidates of the last few decades (that is, until they were fitted with the straitjacket of being their party's nominee).

And certainly no Mo Udalls. The congressman from Arizona, who sought the Democrats' presidential nomination in 1976, has been hailed as perhaps the funniest candidate of recent vintage.

(One of Udall's stump favorites: He said he walked into a barbershop, told the barber he was running for president, and the barber said, "Oh yeah, we were just laughing about that yesterday.")

These are serious men, imbued with lofty senses of mission and thrilled to leave the heavy comic lifting to the tweeters, late-night comedians and Herman Cains.

"I am not running for entertainer in chief," Gingrich declared on last Tuesday night after being trounced by Romney in Florida. No kidding.

In fairness, people close to all of the candidates insist that these men are funny in private. But every politician is said to be "funny in private."

"Funny in private" is the politician's equivalent of a band claiming to be really big in Australia or a teenager claiming to have lost his virginity at summer camp. Who'll ever know?

"I live for laughter," Romney assured Wolf Blitzer, who himself was the source of unintentional comedy at a debate last year when Cain kept calling him Blitz. (Long live the Herman-ator!)

"As soon as you will turn these cameras off," Ann Romney told Blitzer, her husband "will be telling a joke, and we will be laughing."

The problem comes when the camera's on. Romney has a few stock jokes, as all candidates do. He had an unrelenting fondness in Iowa for saying that the "amber waves of grain" line in "America the Beautiful" could refer to corn. It usually drew laughs, mostly of the polite Iowa variety.

(For what it's worth, his father, George Romney, whose presidential hopes were dashed when he claimed to have been "brainwashed" into supporting the Vietnam War, was the butt of this epic stinger from Sen. Eugene McCarthy: With George, the senator said, "a light rinse would have been sufficient.")

Gingrich can be "wry, witty and observational," said his spokesman, R.C. Hammond. But the cameras make it hard.

Indeed, blame the cameras and recording devices, which have never been as ubiquitous or viral in their potential impact. President Barack Obama learned this the hard way four years ago (see "guns and religion," "clinging to"), just as he provided an object lesson in bringing offense with a thrown-off quip when he told Jay Leno that his low bowling ability was worthy of the Special Olympics.

While Obama has a decent sense of comic timing and is adept at delivering written joke lines, many perceive his default bearing to be professorial and aloof — anything but light. The rap that he clings to teleprompters carries an implicit dig that he is overly scripted.

It is akin to critics deriding Romney's delivery as "robotic." ("Ha. Ha. Ha," is how he laughs, always three ha's, with a full stop between each.)

But again, it's dangerous out there.

"I think everybody's so worried about saying something wrong that becomes permanent," said Sen. Lamar Alexander, a kind-of-funny two-time Republican presidential candidate from Tennessee. "Someone comes up to you, shakes your hand, has a camera and the next thing you know, you say the wrong thing and it gets tattooed on your forehead."

Alexander was the subject of a riff from Gingrich last month — maybe as close as you will see to a public giggle fit from the former Speaker of the House. He was being interviewed in New Hampshire by Charlie Arlinghaus, a well-known figure in New Hampshire political and policy circles. Arlinghaus mentioned that in his basement he kept a copy of Alexander's book about running for office. This for some reason turned Gingrich giddy.

"A fine bottle of wine," he said, pretending to hoist a bottle, "and Lamar's book," hoisting with his other hand. "You're between the fine wine and the creamed corn, Lamar," Gingrich said. People in the audience were belly-laughing at this. Newt was on fire.

Guess you had to be there.

When told that his book was the subject of mirth, Alexander volunteered that "Trent Lott told me he keeps my book in his bathroom." (Thanks for the mental image, Senator.)

Could the candidates deploy humor to better advantage? Yes, said Landon Parvin, a longtime speechwriter who has written humor for presidents of both parties.

"The best humor makes you more likable," Parvin said, adding that the most endearing humor is self-deprecating, an area in which these candidates could improve.

"With the absence of humor, you're not dehumanizing and objectifying your opponent, you're dehumanizing and objectifying yourself," said Thaddeus McCotter, a Republican congressman from Michigan who can be hilarious. "In great comedy, the actors believe they are important serious people and the audience knows otherwise."

McCotter ran for his party's 2012 nomination but never got his poll numbers high enough to qualify for the debates. "I was called the anti-candidate," he said, "and evidently you can't argue with that, given the outcome." He now supports Romney.

In light of his recent success at the polls, Romney has shown signs of letting her rip a little. He could not help himself in Florida, perhaps inspired by the presence of McCain, a Henny Youngman devotee (really) who warmed up the crowd with his worn-to-shreds one-liners. (Following a procession of speakers, McCain said "I feel a bit like Zsa Zsa Gabor's fifth husband," who on their wedding night said "I know what I'm supposed to do but I don't know how to make it interesting.")

"I have to tell you one of my favorites," Romney said. "It may not be that funny, but I love it."

All right then: "There's this farmer in Wyoming, he's driving this truck, this livestock truck. He's driving on, gets going too fast, state trooper pulls him over, comes up and says, 'You're going awfully fast, don't you have a governor on this thing?' He says, 'No.' He says, 'No, the smell you smell is from the animals in back."'

Apparently a "governor" is a regulating device found inside an engine, as well as a chief executive trying to be funny, with mixed results.