"I never thought I'd be involved in anything like this," says Lee Vevang, 48, who recently started a lobbying group seeking legislation to deny benefits to illegal immigrants. "But the problem has become so severe it's necessary for citizens like me to get involved."

Julieta Garibay, 24, has a vastly different perspective.

"I call this country my own," says the senior nursing major at the University of Texas at Austin. "So I want to contribute." She leads a group of illegal immigrants who are students fighting for citizenship. "If you want a dream and you want an opportunity, you have to fight for it," she says.

Vevang and Garibay stand on opposite sides of a divisive issue that has spurred volunteers to patrol the border between Arizona and Mexico and produced legislative action and ballot initiatives across the USA.

A similar groundswell led to passage in 1994 of California's Proposition 187, which sought to deny many public benefits to illegal immigrants. But the level of grass-roots activity now is more widespread, says Roberto Suro, director of the Pew Hispanic Center.

"This is starting to become a storm," says Suro, whose organization researches Hispanic issues. "Just the level of activity and number of states we're seeing it in is really unusual. I don't think there's a parallel to it, certainly in recent history."

Hundreds of thousands

In the past 10 years, an average of 700,000 to 750,000 undocumented immigrants a year have arrived in the USA, the Pew Hispanic Center estimates. The population has grown fastest in states that previously did not have a significant immigrant presence.

"We're swamped; no vacancy," says William Gheen, president of Americans for Legal Immigration in Raleigh, N.C. He says North Carolina has "one of the fastest-growing populations of illegal aliens in America, and they're coming here for the licenses and state benefits."

Some activists have grown frustrated with the influx and are determined to take matters into their own hands where they can. During April, hundreds of volunteers for the Minuteman Project, some of them armed, patrolled Arizona's border with Mexico. The group said the vigil, which concluded Sunday, led to the arrests of 335 illegal immigrants. The Border Patrol said the volunteers had little or no effect.

In November, Arizona voters approved Proposition 200, an initiative that requires proof of citizenship to register to vote and proof of eligibility, including legal residency, to collect welfare. "Proposition 200 was a shot in the arm to the anti-illegal-immigration movement," says Kathy McKee, founder and chairwoman of Protect Arizona Now, which launched the petition drive that put the initiative on the ballot.

She says the measure's passage sparked more than a dozen similar bills being considered in the state Legislature.

Similar organizations are trying to get initiatives on state ballots in Massachusetts, Washington, Arkansas and Nebraska, McKee says.

Vevang says she was inspired by the initiative movement in Arizona.

"I'm new to political activism," Vevang says. "Over the years, I paid my taxes and trusted elected officials to do the right thing."

Vevang says she noticed the growing number of illegal immigrants living around Atlanta in the past few years. Her husband, a sheet-metal worker, was temporarily laid off, and she knew others who were competing with illegal immigrants for construction jobs. One day, she saw McKee's Web site and started her own group.

"I would like to end the free buffet for illegal aliens," she says. "To get a driver's license, you should have to be a legal citizen, and to get public services I think you should have to be a citizen. ... The overwhelming majority of Americans feel the same way."

Fight for opportunity

On the other side is Mirla Lopez, 20, who is American in virtually every way other than citizenship. A junior at the University of Texas at Austin, Lopez has not set foot in Mexico since she and her family left there 14 years ago with the help of a smuggler.

It took several tries over two weeks for the family to make it. Upon arrival in the USA, Lopez says, her mother worked as a migrant laborer and tended bar to support her children.

Lopez was able to go to college with the help of a 2001 Texas law. It allows in-state tuition rates for undocumented immigrant students who graduate from a Texas high school they attended for at least three years. Now she fears that the brewing backlash against undocumented immigrants will make it difficult for her to get a good job.

"All I think about is, 'Was there a point in my studying for four years if I'm not going to get a job here?' " says Lopez, a government and pre-law major who has earned as little as $2.50 an hour working in a restaurant. "We pay taxes like everybody else. ... We work just as hard."

Contributing: Patrick O'Driscoll, The Associated Press