His Navy Commendation Medal citation describes a "fire team leader" who led fellow Marines on dangerous reconnaissance missions in Vietnam, "fearlessly trained his men and molded them into a effective fighting force."

But the Vietnam experience also molded an activist for saving lives and stopping war.

Today Bill Durston is a Sacramento emergency room physician, a crusader against gun violence and a vociferous protester against the way America is conducting the war on terror.

He is also a long-shot candidate for the U.S. House of Representatives, seeking to oust Rep. Dan Lungren in the Sacramento region's 3rd District.

Two years ago, peace activists who heard Durston at a Sacramento "Out of Iraq" forum recruited him as an emergency fill-in to run against Lungren. Durston, a Gold River resident and member of Physicians for Social Responsibility, agreed only after he couldn't find anyone else to run.

Now no longer an accidental candidate, Durston, 59, is making his second bid for Congress as a champion for disaffected Democrats furious over the Iraq war and their party's failure in trying to stop it.

In the emergency room of the Kaiser Permanente South Sacramento Medical Center, he mends broken bones and treats cardiac patients. After hours, he makes political house calls, lighting into House Speaker Nancy Pelosi for blocking President Bush's impeachment "for leading us to war on false pretenses."

A physician-activist, he campaigns for universal health care as a "basic human right." An anti-war veteran, he assails the new Democratic majority in Congress for caving in by funding "the ongoing war and occupation in Iraq."

Durston also criticizes presumptive Democratic presidential nominee Barack Obama for vowing to increase U.S. troops in Afghanistan.

He has irked his homeowners association by flying the United Nations flag from his Gold River house in a call for diplomacy to stop the war in Iraq. Despite the 9/11 terrorist attacks, Durston believes the elixir to terrorism is global cooperation and intelligence sharing – not military force.

"You can't stop 19 men armed with box-cutters … by invading countries with tanks, bombers and missiles," he said.

Lungren, who defeated Durston two years ago, 60 percent to 38 percent, calls him a candidate "whose views are unrealistic in the real world."

"I think he (Durston) truly believes we can live in a world threatened by terrorists without using military action," Lungren said in an interview.

Durston attacks Lungren as a pawn of special interests. And he calls the race a "choice between a combat veteran who won't send anybody to a war he wouldn't fight himself" vs. a congressman who didn't serve and has "no idea what war is like."

Durston put off college to enlist in the Marines during the Vietnam War. The decision stunned his father, Al Durston. A bombardier navigator in World War II, the elder Durston only later told his son of his disdain for war.

The son learned on his own. After 21 reconnaissance patrols seeking to track North Vietnamese troop movements and halt mining of a river, Durston concluded war is "a total breakdown of the norms of human social behavior."

He speaks only sparingly of his experiences as a Marine corporal decorated for "courage and composure under fire." He mentions encountering bodies on patrol and engaging in three firefights with an enemy he couldn't see.

But as he describes a seemingly benign event – when his unit came across an old man crossing a rice field in an area controlled by enemy fighters – Durston fights off tears.

"The question was put to me of whether we should kill him," said Durston, whose unit held its fire. "It could have been an incident. I've talked so many times with people who were there who made opposite decisions and had to live with the consequences."

He links tortuous decisions over who was friend or foe in Vietnam to encounters faced today by U.S. troops in Iraq and Afghanistan. And at campaign stops, he hands out copies of a music CD – "War is not a Game" – loosely inspired by Durston's and his father's reflections on combat.

Given that he lost handily to a Republican incumbent two years ago, his candidacy – on the left of Democratic politics – seems quixotic at best.

The Democratic Congressional Campaign Committee – which pledged $2 million to help fellow Democrats Charlie Brown and Jerry McNerney in neighboring districts so far is offering nothing to Durston.

Yet in the 3rd District, spanning Sacramento, Amador, Alpine, Calaveras and Solano counties, the Republican voter registration advantage has shrunk to just four percentage points over Democrats. The margin is smaller than in the 11th District, where McNerney ousted Rep. Richard Pombo in 2006 after being routed in 2004.

Democratic consultant Andrew Acosta said Durston's hopes hinge on a Democratic surge akin to the Republicans' 1994 congressional takeover.

"Two weeks before a lot of people got elected in '94, nobody even knew who they were. It can happen," Acosta said. "Clearly registration in a lot of districts is moving away from Republicans."

GOP consultant Dave Gilliard said independent voters in the 3rd District are generally conservatives unlikely to vote against Lungren, the former state attorney general and one of California's highest-profile Republicans.

Lungren, who calls Durston "out of the mainstream," said he is not taking anything for granted in "the strangest political season I've ever seen."

Though Durston has raised nearly $350,000, Lungren has a 3-to-1 cash advantage. But Durston, who overcame bladder cancer in 1988 and prostate cancer in 2004, said he has no fear of political defeat.

"Our democracy is an experiment," the physician told supporters at a recent house party. "This campaign is part of that experiment."

Call Peter Hecht, Bee Capitol Bureau, (916) 326-5539.