BERKELEY - Brooke Casey hoisted a hand-painted banner and peered down through a light drizzle, surveying the reaction from the evening traffic on Interstate 80.
Perched on a pedestrian overpass, she watched drivers wave through windshields and lean on horns, East Bay commuter applause for the reminder of an anti-war rally that is expected to draw a massive crowd to San Francisco on Sunday.
"This situation has really awakened a sleeping animal," said Casey, 22, waving back at drivers through a chain-link fence. "It's going to get bigger and bigger and be impossible to ignore."
Just then, a head popped out from a car window.
"Give war a chance!" the head shouted. Then another: "Get a job!"
Casey smiled, acknowledging that the debate over a U.S. attack on Iraq has churned passions like few others.
"I have a job," she said.
She is among dozens of organizers who hit high gear this week in their final planning for a party of 100,000 or so this Sunday, one of hundreds of massive peace demonstrations planned this weekend.
Lately, left-leaning activists have been joined by a broadening cross-section of people opposed to a unilateral U.S. attack on Iraq, from church groups to veterans to labor unions, a movement that cuts through the political center.
"It looks like you've got everything out there. It may be the largest expression of anti-war sentiment in history," said Michael Nagler, founder of the Peace and Conflict Studies program at UC Berkeley. "It's also the speed with which it collected. Where we are now probably took 15 years in the Vietnam era."
A coalition of peace groups, churches and others have joined in a full-throttle campaign of phone banks, "blast" e-mails, fliers and banners. At San Francisco-based Global Exchange this week, a cadre of young organizers worked the phones, arranging last-minute speakers, painting slogans on signs, dispatching volunteers to post fliers and drape banners above bridges and ramps.
Their low-budget efforts belie a savvy coordination among disparate activist groups with tactics that run from silent vigils to in-your-face civil disobedience.
Many of Sunday's marchers are expected to be first-timers. Organizers say they have crafted messages to reach a range of political views and levels of tolerance for diatribe.
"The simple message is: We're not ready to go down the primrose path to destruction," said Ted Lewis of San Francisco-based Global Exchange, part of a broad coalition of march sponsors. "There's going to be a big bridge-and-tunnel contingent. People want to express themselves."
The growing show of opposition comes despite recent polls that show a majority of Americans think the administration has presented enough evidence to justify military action against Iraq.
Protesters have learned from the Persian Gulf War, when the "No Blood for Oil" message dominated. That message remains, but organizers now are looking to themes that will challenge efforts to label the anti-war crowd as unpatriotic.
The message will be anti-Bush, but not anti-soldier; it will focus on concerns that an attack on Iraq would make the country less safe. Some organizers are urging no confrontations between protesters and police. Lewis said they are less worried about violence than climate.
"What we don't want to see is rain and small numbers of people."
In some ways, the global protests over the weekend are to build momentum for post-attack activism, said Nancy Snow, assistant professor of communications at Cal State Fullerton.
"It's not just focused on preventing this war this time," Snow said. "I don't think everybody's going to go home when the shooting starts."
Labor unions, which have suffered setbacks under the Bush administration, are among those taking a vocal stance against unilateral action, saying they fear it will harm relations with key trade allies and hurt workers.
"You have Vietnam War veterans who are very skeptical of this, some very conservative folks saying this is not the right thing," said John Dalrymple, executive director of the Contra Costa Central Labor Council. "I can't think of an example where there's been such a rapid escalation of opposition to a foreign policy initiative."
Nagler, of UC Berkeley, credits the expected turnout less to the savvy of activists and more to an administration that has pumped up the volume on terror alerts and the specter of unilateral U.S. military action.
Just what impact the protests might have on the administration is far from clear. The last round of peace marches, held in January in San Francisco and Washington, D.C., garnered little administration response. Nagler said protesters need to convey clear consequences to a U.S. attack.
"There have to be at least some of the protesters saying if you attack that country, I will perform civil disobedience," he said. "I think the administration won't stop unless it has strong reason to believe the country will be ungovernable."
Already, anti-war groups in San Francisco have planned actions for the first business day after a U.S. attack. Planned efforts range from peaceful vigils to blockades. Among the targets: the Pacific Stock Exchange, the Shell office, federal buildings and a military recruitment center.
"Just having a constant presence in the city is going to be disruptive," said Michael, an organizer for the United for Peace and Justice coalition. "The message is that this is not business as usual."