DENVER - Democrats are trying to have some fun at John McCain's expense by passing out oversized buttons emblazoned with the slogan, "Ask Me How Many Houses I Own" - they're suddenly ubiquitous on the 15-block downtown pedestrian mall - and some of the politicians are working the topic into their conversations. When McCain's name came up during a panel discussion earlier today, Minnesota Senator Amy Klobuchar quipped, "People who live in seven houses shouldn't throw stones." And when Kansas Governor Kathleen Sebelius got to the convention podium early this evening, she joked that McCain has added new lines to an old American homily: "There's no place like home. And a home. And home. And home."

So what is McCain's latest strategy to blunt the potential damage of his admission that he can't enumerate the family residences without the assistance of staff?

Play the POW card, shamelessly so.

There once was a time, back in his "maverick" days, when the fawning Washington press corps wrote at great length about how McCain was (supposedly) reluctant to talk about his POW experience for political purposes. This actually wasn't true; during his first congressional race, when McCain was accused of being a carpetbagger because he had moved to the district in order to run for office, he got his opponent to back off by declaring that "the place I lived longest in my life was Hanoi." In the late '90s, when he was ensnared in the Keating S&L scandal, he huffed to inquisitive reporters that "even the Vietnamese didn't question my ethics." Nevertheless, his fans in the Washington press spread the myth that McCain didn't do such things.

Well, he did it yet again last night, playing the POW card on Jay Leno's show. (By the way, this was the celebrity politician's thirteenth appearance on Leno, pulling him even with Jennifer Love Hewitt. Barack Obama has appeared once.)

And when Leno quipped about the candidate's housing cluelessness, thereby suggesting anew to a mass audience that McCain's life bears no resemblance to the lives led by average Americans, the GOP candidate immediate dove for political cover by donning the old prison garb:

"Could I just mention to you, Jay, a moment of seriousness. I spent five and a half years in a prison cell. I didn't have a house. I didn't have a kitchen table. I didn't have a table. I didn't have a chair. And I didn't spend those five-and-a-half years because, not because I wanted to get a house when I got out."

Good grief, what's next with this guy? He must be a blast around the house: "Cindy, I refuse to take out the garbage. I lived in garbage for five and a half years." But seriously folks, I can hear him now, on the campaign trail: "To those who impugn my honor by pointing out that I now support permanent Bush tax cuts for the rich after having voted against them, I need only mention that, after all the suffering I endured for five and a half years, I have now earned the right to change my mind."

Using the POW years for political inocculation may be a shameless tactic, but, for a sizeable number of voters, it probably works. Which is why he has always done it, despite occasional claims that he would never stoop to such a thing. Witness this McCain remark, from 1999: "One of the things I've never tried to do is exploit my Vietnam service to my country, because it would be totally inappropriate to do so."

Although if he keeps trying to duck criticism in this manner, Joe Biden (updating his old quip about Rudy Giuliani's 9/11 mantra) may well be compelled to lament that McCain's candidacy is basically a noun, a verb, and POW.