WASHINGTON — Denouncing a conflict entering its fifth year, protesters across the country raised their voices Saturday against U.S. policy in Iraq and marched by the thousands to the Pentagon in the footsteps of an epic demonstration four decades ago against another divisive war.

A counterprotest was staged, too, on a day of dueling signs and sentiments such as “Illegal Combat” and “Peace Through Strength,” and songs like “The Battle Hymn of the Republic” and “War (What’s It Good For?).”

Thousands crossed the Potomac River from the Lincoln Memorial to rally loudly but peacefully near the Pentagon. “We’re here in the shadow of the war machine,” said anti-war activist Cindy Sheehan. “It’s like being in the shadow of the death star. They take their death and destruction and they export it around the world. We need to shut it down.”

Smaller protests were held in other U.S. cities and abroad, stretching to Tuesday’s four-year anniversary of the Iraq invasion. In Los Angeles, Vietnam veteran Ed Ellis, 59, hoped the demonstrations would be the “tipping point” against a war that has killed more than 3,200 U.S. troops and engulfed Iraq in a deadly cycle of violence.

“It’s all moving in our direction, it’s happening,” he predicted at the Hollywood rally. “The administration, their get-out-of-jail-free card, they don’t get one anymore.”

Speakers at the Pentagon rally criticized the Bush administration at every turn but blamed congressional Democrats, too, for refusing to cut off money for the war.

“This is a bipartisan war,” New York City labor activist Michael Letwin told the crowd. “The Democratic party cannot be trusted to end it.” Letwin said the key to ending the war soon is to bring more troops and their families into the protest movement.

President Bush was at Camp David in Maryland for the weekend. Spokesman Blair Jones said of the protests: “Our Constitution guarantees the right to peacefully express one’s views. The men and women in our military are fighting to bring the people of Iraq the same rights and freedoms.”

People traveled from afar in stormy weather to join the march.

“Too many people have died and it doesn’t solve anything,” said Ann O’Grady, who drove through snow with her husband, Tom, and two children, 13 and 10, from Athens, Ohio. “I feel bad carrying out my daily activities while people are suffering, Americans and Iraqis.”