LOS ANGELES -- When Cardinal Roger Mahony called on Roman Catholics this week to embrace immigrants regardless of legal status, he was not just reiterating the church's long tradition of reaching out to the downtrodden.
Mahony and other US Catholic bishops are increasingly weighing into the debate over what to do about the roughly 11 million undocumented immigrants living in the United States -- a development that is being met with criticism from groups pushing for tougher enforcement of immigration laws.
Catholic leaders have launched a ''Justice for Immigrants" campaign, appealed to President Bush and congressional leaders for a legalization program, and sharply criticized a bill passed by the US House of Representatives in December to tighten border controls.
Among other things, the bill -- now before the Senate -- would obligate churches and other social organizations to ask immigrants for legal documentation before providing assistance.
A handful of bishops have denounced it. Mahony, the leader of the nation's largest archdiocese, went a step further this week. He promised to defy it if it is passed into law.
''I would say to all priests, deacons, and members of the church that we are not going to observe this law," Mahony said after an Ash Wednesday Mass calling on Catholics to ''make room" for immigrants.
Church leaders say they are adhering to Catholic teachings about compassion, but groups pushing for a crackdown on illegal immigration accuse them of trying to bolster their flock by catering to Hispanics, who constitute the majority of undocumented newcomers.
Latin American and Caribbean countries are predominantly Catholic, though in recent decades evangelicals and Pentecostals have attracted millions of new followers in those regions.
''The church is pandering for souls because along with them comes an infinite amount of contributions," said Jim Gilchrist, cofounder of the Minuteman Project, a volunteer civilian border-patrol group that has been criticized by Mahony.
Critics also accuse Catholic leaders of refusing to acknowledge the negative impact of undocumented immigrants and of trying to create a distraction from the clergy sex-abuse crisis.
More than 500 abuse claims are pending against the Los Angeles Archdiocese, which has fought hard against the release of personnel files of accused priests.
''In a clear attempt to create a diversion from the diocese's current problems, [Mahony] ignores the significant negative impact illegals have on our community's hospitals, schools, and jails," Los Angeles County Supervisor Michael Antonovich said.
The church has long been a lobbying force in Washington and in states around the country, advocating for legislation in line with traditional Catholic beliefs such as opposition to abortion and the death penalty.
But bulging immigrant populations and inadequate laws to deal with them pushed the bishops to begin articulating overhauls in the past several years, said Kevin Appleby, director of the Office of Migration and Refugee Policy for the US Conference of Catholic Bishops.
''We don't look at this as, 'Oh, here is a new group of Hispanics we have to compete over with other faiths,' " Appleby said.
In 2003, US and Mexican bishops issued a statement on migration saying that ''more powerful economic nations, which have the ability to protect and feed their residents, have a stronger obligation to accommodate migration flows."
The bishops also said nations were obligated to respect the dignity of migrants ''regardless of their legal status."
Last year, the American church launched the ''Justice for Immigrants" campaign that, among other things, encourages Catholics to write congressional representatives in support of a legalization system for undocumented immigrants.