For Jeff Key, 41, an Iraq war veteran from Hollywood, it was for his fellow Marines who he said couldn't speak up while deployed abroad.
For Amparo Escobar, 22, a student from Santa Ana, it was for anyone who believes in peace. For Alex Robles, 28, a media technician from Pasadena, it was for himself, to show solidarity with the anti-war movement.
On Saturday, on the eve of the fourth anniversary of the invasion of Iraq, the protest cascaded down Hollywood Boulevard.
Set to coincide with rallies across the nation, it aimed to show that as the war has progressed, opposition has not wavered.
Though smaller than organizers had predicted, the event still drew a crowd of 5,000 to 6,000 after it began at noon at Hollywood and Vine, according to the Los Angeles Police Department.
Allan Widmeyer, 52, drove down from Oxnard to march for the more than 3,000 dead and thousands of wounded soldiers.
"When people look back on this age, they're not going to cry about the terrible things that happened -- they're going to cry about the people who stood around and did nothing," he said as the crowd marched past. "I don't want to be one of those people."
Nor did Key, who wore his desert-print camouflage pants and hoisted a sign in protest. A former lance corporal who served near the Iran-Iraq border, he came home with a noncombat injury and left the military.
He has written a play about his experiences and has become an ardent activist against the war he once helped fight.
"It makes this nation less safe," he said. "I saw the oppression of the people of Iraq for the good of corporations."
The marchers made their way to Sunset Boulevard, then back up to the corner of Hollywood and Highland Avenue.
Along the way, activists voiced their support for everything from gay rights to lower bus fares to religious tolerance.
It was a surreal scene, with marchers tromping across stars adorned with the names of famous movie stars and television personalities.
Costumed characters intermixed with the demonstrators. Zorro, apparently unaffiliated with any group, paced around with his sword in his scabbard. Batman helped park cars. Charlie Chaplin enjoyed a snack as he watched the march unfold.
At the end of the route, in between grand movie palaces and a luxury shopping center, a group of counter-protestors waved flags and accused the marchers of supporting terrorism, communism and the nation's enemies.
"There's a bunch of nickel brains out here, idiots, who don't know what they're talking about," growled Matt Fine, 24, a North Hollywood file clerk. "I'm here supporting the troops. Those people aren't."
On the street, marchers bore mock coffins draped with American flags, symbolizing dead soldiers killed in the line of duty. Most were quick to say that they opposed the war itself, not those fighting it.
"C'mon, bring our boys and girls home," said Kelli Diana, 38, a West Los Angeles trade show producer. "I believe in the military, I support the military. But just sending more people is not the answer.
"... All of a sudden, it's four years later, and we're still sending more people."