IRVINE -- Laurie Lisonbee worried about illegal immigration but figured it was somebody else's issue -- until she saw hundreds of thousands of immigrants and their supporters marching across her TV screen.

Soon, Lisonbee had recruited several friends to attend a demonstration by the Minuteman Project, a volunteer group that patrols the border to keep out illegal immigrants. Now, the 51-year-old art professor checks the group's Web site daily and plans a summer trip to the Mexican border to help build a fence.

Minuteman organizers say this spring's marches have proved to be an unexpected recruitment tool for Americans who feel uneasy about the burgeoning immigration movement but may have considered the organization a pack of gun-toting vigilantes.

"We're not trying to be more mainstream -- mainstream has found us," said Stephen Eichler, the group's executive director. "They're saying, 'These guys actually have teeth, they don't all chew tobacco, they don't all have a gun rack in the back of their truck.' They're saying, 'They believe what I believe,' and they're joining us."

Lisonbee, a registered Republican, said only one issue matters to her now.

"My vote will go to the candidate who's the toughest on immigration, whether they're Democrat or Republican," she said from her home in Orem, Utah. "Before, we were pretty much the types of people who would call our congressmen and not take to the streets. But that's all changed now."

The Minuteman Project first gained attention last year when Orange County resident and former tax accountant Jim Gilchrist helped lead its first 30-day patrol of the border in Arizona. The group has added mainstream political tools, including a network of local chapters and e-mail lobbying campaigns.

In December, Gilchrist, a former Republican, ran as a third-party candidate in a special House election in Orange County, Calif., finished a respectable third with 25 percent of the vote.

Since this spring's huge pro-immigrant rallies, 300 people nationwide have applied to start local chapters, according to Eichler. The group's goal is 500 chapters by December and a membership of 1 million within 1 1/2 years, Eichler said.

Eichler claimed the organization's membership has climbed to more than 200,000.

But Heidi Beirich, deputy director of the Southern Poverty Law Center's Intelligence Project, which monitors the Minuteman Project for racist rhetoric, said that estimate appears to be ridiculously high. She offered no estimate of her own.

"At the border during this last outing, they had maybe 50 people. If they have 200,000 people, it doesn't seem right," she said.

Beirich also questioned the premise that pro-immigrant rallies will help the Minuteman Project. She said many recruits may attend one or two rallies, but leave after they discover what she called the group's extremist attitudes.

"They get in there and they're like, 'My God, I didn't sign on for this,"' she said.

In the coming weeks, the Minuteman Project plans to set out in a caravan from Los Angeles to Washington, with stops in 13 cities, including President Bush's vacation haven of Crawford, Texas. It is also raising money to build a private fence along parts of the California-Mexico border.

Increased security along the border is a popular idea on Capitol Hill, where the immigration debate will soon resume. How to treat the approximately 11 million illegal immigrants now here is where Congress splits -- a House bill would criminalize the immigrants, a Senate bill would offer guest worker status and a potential path to citizenship.

David S. Meyer, a professor of sociology and political science at the University of California, Irvine, said the growing Minuteman movement has "stiffened the spine" of conservative politicians who might otherwise be wary of publicly identifying with the organization's views.