At first blush, it would seem to be a positive for Obama that he is hard to mock. But on second thought, is it another sign that he’s trying so hard to be perfect that it’s stultifying? Or that eight years of W. and Cheney have robbed Democratic voters of their sense of humor?

Certainly, as the potential first black president, and as a contender with tender experience, Obama must feel under strain to be serious.

But he does not want the “take” on him to become that he’s so tightly wrapped, overcalculated and circumspect that he can’t even allow anyone to make jokes about him, and that his supporters are so evangelical and eager for a champion to rescue America that their response to any razzing is a sanctimonious: Don’t mess with our messiah!

If Obama keeps being stingy with his quips and smiles, and if the dominant perception of him is that you can’t make jokes about him, it might infect his campaign with an airless quality. His humorlessness could spark humor.

On Tuesday, Andy Borowitz satirized on that subject. He said that Obama, sympathetic to comics’ attempts to find jokes to make about him, had put out a list of official ones, including this:

“A traveling salesman knocks on the door of a farmhouse, and much to his surprise, Barack Obama answers the door. The salesman says, ‘I was expecting the farmer’s daughter.’ Barack Obama replies, ‘She’s not here. The farm was foreclosed on because of subprime loans that are making a mockery of the American dream.’ ”

John McCain’s Don Rickles routines  “Thanks for the question, you little jerk”  can fall flat. But he seems like a guy who can be teased harmlessly. If Obama offers only eat-your-arugula chiding and chilly earnestness, he becomes an otherworldly type, not the regular guy he needs to be.