The New York Post gleefully labeled him "Baghdad Sean." The tabloid even offered a top 10 list why Penn would be a great arms inspector, saying he had his own biological weapon "foot-in-mouth disease," and knew something about bombs because of his work on the movie Shanghai Surprise.
Penn even received bad press about the amount of bad press devoted to his anti-war efforts. "Dead man talking," muttered The Associated Press, unable to resist punning the title of one of the star's movies. "A star is scorned," read a Washington Times headline.
Penn has claimed his political activism cost him a movie role and has sued producer Steve Bing over the matter. Bing promptly counter-sued Penn.
The conservative press has been particularly hard on celebrity involvement in opposing war in Iraq.
"Thank God for America's valiant army of really dumb celebrity-intellectuals, without whom there'd be almost nothing to smile about," crowed the Weekly Standard magazine last month.
The conservative National Review titled a piece about John Le Carre, "Tinker, Tailor, Soldier, Jerk," after the spy writer released a statement rebuking U.S. foreign policy.
While most famous faces that have spoken out have been against war, a handful have voiced their support for President Bush, including Harrison Ford, Tom Cruise, and Dennis Miller. Activists on both sides of the issue have accused their ideological foes of singling out celebrities instead of focusing on the issues.
Anti-War Experts Are Ignored, Complain Celebs
Even those involved in the anti-war movement admit that celebrity activism is not ideal.
In an interview with Canadian radio, George Clooney conceded his opinions are no more informed than the average American's.
"I'm not the person to be sending messages to — I'm not smart enough and I don't know enough about what's going on," Clooney said. "I just want it to be talked about and discussed a lot more before one man makes a decision to go in and bomb."
The comedian and actress Janeane Garofalo, one of the most vocal celebrities among anti-war activists, agrees.
"I absolutely realize that a celebrity spokesperson is not ideal," she says. "I don't like it and I don't like to do it."
Garofalo thinks the media has ignored policy experts opposed to an Iraq war and focused instead on celebrities in part to discredit anti-war protestors.
"It's clearly biased and loaded to make the actor look foolish, thereby marginalizing the movement," she says.
But she defends her vocal stance against those who say celebrities should stick to their scripts.
"That's like saying everyone in the food-service industry is not entitled to speak out," she complains.
Some people think celebrities are a natural choice for the movement, however.
"Celebrities command a lot of attention — it's the new religion, it's a contemporary religion," said Boyd. "People pay attention."