In communities up and down Route 101, the highway that runs parallel to Marin County's spectacular coast, opposition to the war in Iraq has mobilized liberal activists. Many of the same people who marched against the Vietnam War have held nightly peace vigils. In West Marin, a group of local feminists has "bared witness," using their nude bodies to spell out "PEACE," and the Marin County Democratic Central Committee unanimously passed a resolution calling on Congress to reject authorization of the use of force in Iraq. A Methodist pastor recently called on Americans to abandon armed violence.

One hundred miles inland and a world away politically, ministers preach that killing Iraqi soldiers does not violate the Ten Commandments -- that "in God's view there is a time for war and that time is now." Republican operatives say that the turnout at demonstrations in support of U.S. troops "wipes the floor" in the competition with much smaller peace rallies.

Liberal, affluent Marin County is a stronghold of what became known in the wake of the 2000 presidential election as "Blue America." Not only did Al Gore decisively carry the county, but almost every elected official strongly backs gun control, gay rights and a woman's right to abortion. The inland counties of El Dorado and Placer are firmly in "Red America," where George W. Bush trounced Gore, and on most social issues, the mainly working-class families who live there can be counted on to oppose the views of their neighbors on the Pacific Ocean.

Widening the chasm that divides these two subcultures of American politics is a new and emotional issue -- the war in Iraq. Interviews and national polls suggest that the use of force to destroy Saddam Hussein's government has become another litmus test in the clash of values that has increasingly defined political campaigns on the national and local level. The war in Iraq is an issue that pits the liberal and moderate wings of the Democratic Party against each other, while producing near unanimous support among conservatives and Republicans.

This war is part of "the constellation that is of most interest among those who call themselves liberal Democrats, and, on the Republican-conservative side, it is their ying to the liberal yang," said Andrew Kohut of the Pew Research Center. Don Sipple, a Republican consultant, has described the split as a conflict between those who believe in discipline and those who believe in therapy.

Unlike abortion, perhaps the single most important issue separating Red and Blue America, the war, at the moment, works to the decisive advantage of the political right while fracturing the Democrats by isolating the antiwar, liberal activist wing, including the Marin County demonstrators, from many of party's regular supporters.

The problem for Democrats here and nationally is clear in poll data. A Pew survey released last week found that opponents of the war, even in states that voted for Gore, are in a distinct minority. When asked, "Do you think the U.S. made the right decision or the wrong decision in using military force against Iraq?" residents of Blue states supported using military force, 67 percent to 27 percent -- numbers not so different from those in Red states, where people supported using military force, 75 percent to 18 percent.

The Pew survey found a significant split between liberal Democrats, who opposed the war 54 percent to 42 percent, and moderate Democrats, who supported it 2 to 1.

Those numbers are reflected in Marin County and the San Francisco Bay Area, where the Democratic and liberal leadership is solidly against the war, while many of their constituents are not with them. The California Field Poll released last week showed that almost two-thirds of those surveyed support the war.

Still, no recent issue has mobilized activists in Marin County as strongly as the war.

"I've been in a lot of political organizing since the '60s, and we have never seen anything like this," said Alan W. Barnett, who serves as co-chairman of the Marin Welfare and Immigration Network, and chairman of the Marin Coalition for Immigrant Rights and of Marin Advocates for Justice.

In El Dorado and neighboring Placer County, in contrast, the war has received the vocal support of the area's large number of military families, the Republican Party and the Christian right. The Field Poll found support for the war in the area at 79 percent -- 3 percentage points higher than in the state as a whole.

The Rev. George Dawson, a Southern Baptist minister and retired Air Force master sergeant, has preached from the pulpit of his church that "we are doing what needs to be done."

In January, disturbed by television reports of demonstrations as her son Glen shipped out to Kuwait, Ginny Nahmens formed MOM (Mothers of Marines) in El Dorado County. With the backing of the Boys and Girls Club, the Rotary Club and the Chamber of Commerce, her organization has received wide community support, converting the Marine Corps Reserve's Toys for Tots program into a large care-package program for service members in Iraq.

Nahmens said she is not angry at antiwar demonstrators. "The part I appreciate is that they don't want my son to get killed. They don't want anyone to get killed. But I know that there are certain things that have to be done." Then, she added on a harsher note: "If Saddam was doing to dogs and cats what he is doing to humans, if he was dropping dogs into acid slowly, that same group would be up in arms."

The ideological gulf between the activists of Marin and El Dorado counties epitomizes what University of Michigan political scientist Ronald Inglehart has characterized as the clash between "post-materialist" communities, in which affluence has shifted public priorities to such "quality of life" issues as the environment, peace and personal fulfillment, on the one hand; and, on the other, more traditional "materialist" communities, in which the focus is more on military security, economic growth and fighting crime.

Many of Marin's voters are part of the Democratic Party's most rapidly increasing new constituency: white, affluent, well-educated professionals, many with doctorates and law degrees. These voters have undergone a realignment, shifting their allegiance from an increasingly conservative Republican Party to the pro-abortion rights, pro-gun control, increasingly secular Democratic Party of today.

Just 23 years ago, the voters of Marin backed Ronald Reagan over Jimmy Carter by about 15 percentage points, 57.3 to 42.5. In 2000, the voters of Marin and neighboring Sonoma County backed Gore over Bush by an extraordinary 32 percentage points, 62 to 30.

Marin, together with most of neighboring Sonoma County, makes up Democratic Rep. Lynn C. Woolsey's 6th Congressional District. El Dorado and the counties that run northward along the Nevada border to form the 4th Congressional District, represented by John T. Doolittle (R), have undergone their own realignment. There, working- and middle-class whites have abandoned Democratic loyalties as the party leadership and local party activists have increasingly embraced social liberalism and environmentalism, while the GOP has formed increasingly strong alliances with conservative churches, gun owners, the property-rights movement and small-business owners.

In 1960, El Dorado and Placer counties cast slim majorities for John F. Kennedy over Richard M. Nixon, even though Nixon was a native Californian. By 2000, the same two counties backed Bush over Gore by 22 and 23 percentage points, respectively.

The blue-collar voters who were committed to the party of Franklin D. Roosevelt and Harry S. Truman have turned against an environmentalist Democratic Party that has imposed regulations they see as closing the mines and mills, Republican consultant Rick Staats said. "It's a classic example of the Republican Party moving away from the country clubs to the small guy who used to be a Democrat," he said.

Census figures document what Staats described. In the solidly Democratic 6th District, the median family income in 1999 was $69,561, $20,730 more than the national median of $48,831. In the 4th, it was $43,389, $5,442 less than the national median. In the 6th, there are 8,089 houses worth $1 million or more; in the 4th, just 152.

The Rev. John Auer, preaching last week at the United Methodist Church here in Marin County, said he had gone to a ballgame in Fresno -- a city in the 19th Congressional District, another bastion of Red America -- and tried to count the number of cars with "No War in Iraq" bumper stickers. "You know how many I counted? [Only one.] You are looking at him. . . . We felt we were in a different place, a place where perhaps more of us need to be."

Auer acknowledged to his parishioners that advocacy of peace is a tough sell. "Our faith in the 'timing' of things under God, as in 'to everything there is a season,' makes us seem crazy to others." In Auer's view, the terrorist attacks of Sept. 11, 2001, were an opportunity for Americans "to give up all our former illusions of power to dominate and to control, to make our own way in this world. For only as we die to ourselves may we hope to be born again to a larger identity, to a larger sense of ourselves as connected, ourselves as related to all the earth."

The hurdle facing not only Auer and his allies in the peace movement but also the Democratic Party generally was evident even here in the heart of Blue America one recent afternoon, when supporters of the war in Iraq were welcomed in Marin's San Anselmo with just as many waves and honking horns as the peace demonstrators waving placards across the street.

"Wars are good," declared Vietnam War veteran Drew McEachern. "We are here because of wars. We are here speaking English because of wars that we've won. We've got people demonstrating on two corners; where else could you do that? That's because of wars we've won."

"I've been in a lot of political organizing since the '60s, and we have never seen anything like this," says Marin activist Alan W. Barnett, here at a rally. Ginny Nahmens of Placerville formed Mothers of Marines and has a son in Kuwait. "There are certain things that have to be done," she says of the war.