-- The police chief of this tiny whitewashed New England town has crafted his own border-control policy -- he has charged illegal immigrants from Mexico with trespassing in New Hampshire.

The novel legal strategy has made a minor celebrity of W. Garrett Chamberlain. The 36-year-old police chief hops to his feet and deposits a pile of letters on his desk, from Alaskans and Californians, Border Patrol agents and soldiers in Iraq, all applauding his initiative. Fox News commentators have called, too, seeking his views on national immigration policy.

Chamberlain, who has served as chief for three years, describes his actions as born of frustration with the federal government. His officers had discovered illegal immigrants several times, but immigration agents declined to detain them.

"I'm just saying: 'Wait a minute. We're on heightened alert and it's post-9/11, and I'm going to let an illegal immigrant who I don't know from Adam just walk away?' " Chamberlain said. "That's ridiculous. If I find you are in my country illegally, I'm not going to worry about political correctness. I will detain you."

So another shot is fired in the often-testy debate over U.S. immigration policies and border security, a battle fraught with political and ethnic anxieties. Already, another police chief, Richard E. Gendron in nearby Hudson, N.H., has followed suit. A few days ago, Gendron brought trespassing charges against two illegal immigrants from Mexico after his officers stopped a van with a broken headlight. Several police chiefs in New Hampshire have suggested that they might pursue such tactics in the future.

For now, however, their eyes are trained on New Ipswich, a town of 4,200 people set in green hills just north of the Massachusetts border. The Mexican immigrant, Jose Mora Ramirez, faces trial on the trespassing charge in July. The two Mexicans arrested in Hudson will be tried later that month.

The Mexican consulate has hired an attorney for Ramirez, fearing that a court may uphold the trespassing charges and so set a national precedent.

"The Mexican government was understandably worried that this could become the charge du jour across the country," said Claire Ebel, executive director of the New Hampshire American Civil Liberties Union, which helped find the lawyer for Ramirez. "They worry about vigilante police chiefs who will round up people based on the color of their skin."

New Hampshire is 96 percent white but has seen a swell of immigration from south of the border in recent years. The Latino population, in particular, has grown in Manchester and Nashua. These two cities have at least 20,000 Latinos, of Uruguayan, Puerto Rican, Dominican, Mexican and Central American descent, and there are now two Latino members of the 424-member state House of Representatives.

"The $64,000 question is why these police chiefs are doing this," said state Rep. Hector M. Velez (D), who was born in Pennsylvania and served in Operation Desert Storm before moving to Manchester, about 20 miles northeast of New Ipswich. "They talk terrorism, but none of these guys were looking for anything except hard work. You ask me, some people are afraid of the unknown."

The two police chiefs insist that racial and ethnic considerations played no role in their calculations. (The populations of New Ipswich and Hudson are 98.6 and 96.3 percent white, respectively.) They note that their officers made the arrests during routine traffic stops at night.

"Look, if you came here legally, fine," Chamberlain said. "I greet you with open arms."

He and Gendron reserve much of their annoyance for the federal government, which they say spends billions of dollars on homeland security even as the southern and northern borders remain sieves. (U.S. Immigration and Customs Enforcement, or ICE, estimates that 8 million illegal immigrants live in the United States; about 465,000 are fleeing deportation orders.) "I just find it hard to believe that we spend billions of dollars on high-tech security stuff and then we let 8 million people come across our border illegally and say nothing," Gendron said. "My son is with the Army in Iraq, and he says the biggest challenge is to tighten the border. Why is it any different here?"

Chamberlain was nudged into action in the summer of 2004, when he stopped a van for speeding along New Ipswich's short main drag. He found 10 Ecuadoran men inside, all of whom readily admitted they lacked legal papers. Chamberlain placed a phone call to ICE.

"The feds were, like, 'Whatever. Just give them a ticket and let them go,' " Chamberlain said. "I was shocked."

After that, the chief sat down with a local prosecutor and tried to find a legal foothold. They settled on New Hampshire's trespassing law, which states: "A person is guilty of criminal trespass if, knowing he is not licensed or privileged to do so, he enters or remains in any place." They planned to demand that illegal immigrants report to an immigration office within 72 hours of pleading guilty.

New Ipswich officials checked with the state attorney general, who gave a modified thumbs up. "It's a novel interpretation," Assistant Attorney General Robert Carey said. But he added: "We weren't aware of any New Hampshire case that would preclude that prosecution."

The New Hampshire ACLU takes a dimmer view.

"This is a preposterous interpretation of a state law intended to apply to private property," said Ebel of the state ACLU. "You have to turn your mental clock back 100 years to believe that a police chief has the right to set federal policy."

Manny Van Pelt, a spokesman for the federal immigration service, declined to comment on the legal strategy. He noted that most police departments choose to tap into the federal government's criminal database and consult with ICE agents on arrests. "The reality is that the immigration system was never set up to arrest every single illegal immigrant," Van Pelt said. "You'd have to build prisons from the West Coast to the East Coast to do that."

New Hampshire has come late to wrestling with immigration. While French Canadians once poured in to work in lumber and textile mills, the state's modern growth has been fed predominantly by white residents moving north from Massachusetts. They have often settled in towns where historically much stock was placed on fitting in.

"One has to recognize that a lot of people coming from Massachusetts are to some extent trying to leave behind the issues of immigration and ethnicity," said Prof. David H. Watters, director of the Center for New England Culture at the University of New Hampshire. "There is also an old tradition in New Hampshire of 'warning' people who were not born there out of towns. That sensibility still survives."

Interviews with a dozen residents of the two towns found nothing but support for the chief. "The poor chief is just doing his job," Diane Slyman said as she sipped coffee in a New Ipswich bagel shop. "We want to live in a small town where we feel safe."

Gendron has heard much the same at his end. "I've got pretty close to 80 e-mails, and only one was negative," he said. "And that person was concerned that if illegal immigration slowed down, the price of lettuce might go up."

Staff writer Michelle Garcia in New York contributed to this report.

W. Garrett Chamberlain says he is frustrated that federal officials have declined to detain illegal immigrants.