Politico asked the question that is on everyone’s lips today: “Is Herman Cain serious?” The higher the former pizza magnate climbs in the polls, the more relevant that question becomes. But so is the question of temperament. The border fence brouhaha is another example that calls both into question.

Discussing illegal immigration at a campaign stop in Tennessee on Saturday, Cain said, “We’re going to have a real fence. 20 feet high with barbed wire. Electrified. With a sign on the other side that says, ‘It can kill you!’ ”

Anticipating the criticism he knew he’d get, Cain went on to say, “Then I get criticized, ‘Mr. Cain, that’s insensitive.’ What do you mean insensitive? What’s insensitive is when they come to the United States across our border and kill our citizens and kill our border patrol people. That’s insensitive.”

Asked about this the next day on “Meet The Press,” Cain tried to slough it off as a joke.

Visit msnbc.com for breaking news, world news, and news about the economy

That’s a joke. That’s not a serious plan. That was a joke. I’ve also said America needs to get a sense of humor.

Hardy har har.

And then there Cain was in Arizona yesterday with sketchy Maricopa County Sheriff Joe Arpaio, flipping his flop on the entire matter.

Let me first say, it was a joke. And some people don’t think it was a good joke. And it is probably not a joke you are supposed to make if you are a presidential candidate. I apologize if it offended anyone. Mea culpa. Mea culpa. Mea culpa. . . . I don’t apologize for using a combination of a fence, and it might be electrified. I’m not walking away from that. I just don’t want to offend anybody.

What irks me about each of these video clips is Cain’s tone and demeanor. He’s not joking. He’s deadly serious. And that “mea culpa” business reeks of the condescension used by those busted by their own insensitivity, callousness or ignorance.

Cain is right. America does need to get a sense of humor. Joking about illegal immigration and killing those who might run afoul of his plan to stop it is not the place to start.