When a group of illegal Irish immigrants in the Bronx started agitating for visas last year, one of the first politicians they looked to for help was Rep. Peter King, a Republican of Long Island. That was before he introduced a bill that would make them criminals.

Last December, Mr. King’s enforcement-only immigration bill, which would make unlawful presence a felony and build a fence along the border with Mexico, passed in the House. To Irish immigrants who had hoped Mr. King, a longtime champion of Irish causes, would broaden immigration laws, their chances of becoming legal were suddenly much slimmer.

An Irish fury has been mounting in response. While there are only an estimated 40,000 illegal Irish immigrants in America, local community leaders have come out as strong proponents for immigration reform. “For 20 years, he’s been the best friend the Irish have ever had in America,” the editor of the Irish Voice newspaper and a leader in the Irish movement for immigration reform, Niall O’Dowd, said. “But I can’t quite equate the person who was a great fighter for the underdogs with the one who wants to jail illegal immigrants and anyone who helps them.”

Mr. King said the bill, which he coauthored with Rep. James Sensenbrenner, a Republican of Wisconsin, has been misrepresented, but the bottom line is that after September 11, 2001, a blind eye cannot be turned to the estimated 12 million illegal immigrants in America. “They create the impression that the whole thing is targeted at them and they ignore that the situation has changed since September 11,” Mr. King said of the Irish response. “If it’s wrong for a Muslim to be living illegally on Atlantic Avenue, you can’t make a distinction between that and an Irish person.”

Instead, the solution to securing America is closing the borders and cracking down on illegal immigrants through workplace enforcement and criminal consequences, he said.

Critics say such an enforcement only bill will not lead America to any better sense of who lives within the country’s borders because illegal immigrants will simply go further underground. President Bush and the secretary of the Department of Homeland Security, Michael Chertoff, have said deporting them is impossible. Mr. King also said he feels deporting all 12 million is not realistic, but that legalizing them will only exacerbate the problem by attracting more illegal immigrants seeking similar treatment.

Angered by the direction the government appeared to be taking with regard to immigration, more than 1 million last month rallied across the country to the slogan, “We are not criminals.”

Mr. King’s response: “If you break the law, you are a criminal.” But he also said his intention is not to make immigrants or their supporters into felons. Placing the blame largely on the Catholic Church, he said the warning by the archbishop of Los Angeles, Cardinal Roger Mahony, that the House bill would put priests behind bars was “sinful.”

While it includes a measure that in effect makes aiding an illegal immigrant a felony, Mr. King said the bill was created to crack down on smugglers, not priests. Moreover, his intention, he said, was never to make unlawful presence a felony but a misdemeanor.

Defying Mr. Bush, Mr. King also stands by his rejection of any program to grant legal status to illegal immigrants and that any “guest worker” program should be delayed until the country’s borders are secured. If the Senate, whose leadership is looking to pass such a legislative program, succeeds, Mr. King said the House would block it. “This is an amnesty. What it does is legalize people who are living here illegally,” he said. “If it does go through, we go to conference and I don’t see the House passing anything that looks like amnesty.”