"Maybe his solution will be to get out his small varmint gun and drive those Guatemalans off his lawn."

This line, from yesterday's blogger conference, is making quite the sensation. And rightly so! McCain hilariously combines two embarrassing things about Romney:

McCain made his comments after he was asked his opinion about GOP rivals opposing the Senate measure.

Referring to Romney's stance, McCain said: "Maybe I should wait a couple of weeks and see if it changes because it's changed in less than a year from his position before."

Then, with a chuckle, he made his cutting quip that referenced two embarrassing episodes for Romney in the past six months.

Romney has faced criticism for calling himself a lifelong hunter even though he joined the National Rifle Association in August and officials in four states where he has lived said he never took out a hunting license. Defending himself, he said in April, "I've always been a rodent and rabbit hunter, small varmints, if you will."

Also, The Boston Globe reported late last year that several illegal immigrants, including at least one from Guatemala, worked at the lawn care company that worked on Romney's two-and-a-half acre property in a Boston suburb for a decade. His aides have said that Romney was not aware of the workers' status, and that the owner was in the country legally.

Romney spokesman Kevin Madden said his boss' opposition to the immigration measure has been clear. Madden counter-punched McCain, saying: "It seems that certain candidates who brokered this flawed plan are having a very difficult time grappling with or coming to terms with the political fallout that has ensued in a substantive manner."

Hey, that "counter-punch" isn't even mildly amusing!

How much can a great joke help a candidate or persuade people about an issue? Can you think of some good examples of jokes that worked beyond just being funny? The main one I think of is Reagan's line: "I am not going to exploit for political purposes my opponent's youth and inexperience. " That defused the serious issue of his age (or so they say).

McCain's great joke is kind of different, because it initially strikes us as bizarre. You need to know about two news stories to get it. And it's got the image of threatening to shoot people, which can disturb and confuse anyone who doesn't understand the joke and which resonates badly with McCain's own negative.

Reagan's joke was warm and flipped his own negative to a positive. It wasn't the slightest bit nasty toward his opponent, Walter Mondale, who wasn't too young himself. Saying it, Reagan seemed entirely good-hearted. McCain said something negative about the other guy, and it seems to express McCain's own negative aspect of anger. The joke puts a picture a crazy gun-waving character in your head. The ordinary person, who is more likely to know McCain's reputation as a hothead than the varmints and Guatemalans background stories, may instinctively put McCain's face on that crazy guy.

When I heard the joke, the part that seemed most discordant to me was that it named a specific ethnic group. Normally, in the immigration debate, we speak of Hispanic people. Why is it suddenly Guatemalans? Once you read the background news stories, you know exactly why he said that and it becomes especially funny. But all those things you think in the lag time between hearing the joke and getting the varmints-and-Guatemalans background are a big drag on the political effectiveness of the joke.

IN THE COMMENTS: Froggyprager thinks the need to explain the joke is the reason it will be politically effective:

The bloggers will talk about it, people need to figure out what it means, then the main stream media will highlight the problems with Mitt that McCain wants to point out to the world.

So the joke's weirdness gets your attention, then you require an explanation, and then everyone -- like me, here -- has to talk about the joke and how they understood it, and that generates a new story about how everyone's been talking about it. And the two stories that are harmful to Romney get retold and retold in the process.

John Stodder writes:

The joke is very "inside-baseball." It's perfect for McCain's real audience, his erstwhile supporters in the media who "get" all the references. The mind that gestated that joke is the same mind behind McCain's misguided political strategy. He's such an admirable guy, but unfortunately, he is afflicted with the same inability to talk to normal people as the other longtime senators in the race, Biden and Dodd.

Romney is starting to remind me of someone I'm sure he'd rather not be compared to: John Kerry.

Uh-oh. From Massachusetts too.