Since the campaign ended, the stakes have changed. He has yet to understand the lesson learned by Steven Chu, his secretary of energy. Asked what he likes least about his new job, he replied: "The fact that I'm constantly being told that I have to be careful what I say to the press and in public. I can't speculate out loud anymore. Everything I say is taken with total seriousness."

Even laughter can be suspect. Steve Croft, the president's interviewer on "60 Minutes," suggested the president might be "punch drunk" when he chuckled aloud in discussing the crash of the economy. "Gallows humor," the president later called it. But that doesn't work for a president, whether hot or cool. Most of us didn't expect Bill Clinton to feel our pain, and we don't expect Barack Obama to laugh at it.

None of this will matter much if, as he suggested it would in his press conference this week, the economic crisis soon eases. He'll get the credit, and that's how it should be. But there should be a bright line between behaving as the commander in chief and entertaining as a celebrity in chief.

The history of Washington and Hollywood eager to trade places is a long one. Politicians and entertainers imagine themselves as stars in the same galaxy. Bette Davis and Humphrey Bogart campaigned for FDR, to the dismay of studio executives (that, too, seems quaint today). JFK enjoyed the company of Marilyn Monroe and was pals with Frank Sinatra (who later liked to hang out with the Reagans). Barbra Streisand sometimes slept at the White House (in the Lincoln Bedroom, of course) during the Clinton years.

Said Gerald Ford, in another context, "If Lincoln were alive today, he'd be spinning in his grave." Lauren Bacall understood the "natural attraction" between Washington and Hollywood. "They have access to real power, and we sing, dance and act."

The modern president crosses that bright line between statecraft and stagecraft at his peril. Obama would do well to remember that statecraft is what we elected him to manage. He should leave the barbs and yuks to the professionals.