Most Americans who've opposed the war are anonymous faces in the crowd, and their protests haven't cost them all that much.
But for famous faces like actor Martin Sheen, freedom of speech could be costly to his career. And he says it ought to be.
"You have to pay something," he said. "It has to cost you something, otherwise you have to question what it's worth.
Stars Hit Hard, Amid Controversy
He and other anti-war celebrities, including Tim Robbins and Susan Sarandon, have been labeled "unpatriotic," or "un-American."
The Dixie Chicks, for example, won several Grammys this year, but their criticism of President Bush still has radio listeners calling for stations to quit playing their music, and many stations have.
Columnist Richard Johnson of the New York Post headlined more than a dozen entertainers as "Saddam Lovers" and urged readers to boycott their work.
A Florida appearance for Sarandon was canceled, as was a celebration of her and her partner Robbins' film Bull Durham at the Baseball Hall of Fame. The president of the museum, who worked in the Reagan White House, decided their views might endanger American troops. He did not explain how.
"A chill wind is blowing in this nation," Robbins said.
In Washington, Robbins criticized the political climate in which his right to express his views has come under attack.
"Isn't it what we were fighting for there ... to spread democracy, to give the Iraqis the right to express their opinions in a public forum?"
Return to McCarthyism?
All this reminded some of the McCarthy era's blacklist that barred those even accused of communist sympathies from working in films or on television.
Actor Mike Farrell believes it could happen again.
"We know there have been organized attempts to get people fired from their jobs," Farrell said.
For showbiz people, it's no idle concern, says historian Steven Ross.
"Movie stars who get bad publicity, who are thought to be unpatriotic, are going to be perceived as box office poison," he said.
The bad publicity is a fact. How the public responds at the box office remains to be seen.