The Vatican's representative to the United Nations will headline an array of experts on immigration and faith at Duquesne University Thursday.

About 200 people have already registered to hear Archbishop Celestino Migliore, permanent observer to the U.N. from the Holy See, and many others at the all-day seminar, "Immigration and the Plight of Immigrants: Politics, Policy, Morality." The seminar is free, but registration is required at www.faithandpolitics.duq.edu or 412-396-6388.

"Immigration is probably the major issue in the election this year," said Francesco Cesareo, dean of the McAnulty College of Liberal Arts at Duquesne, who organized the forum.

"There has been a tension between the bishops and the legislators over this question, particularly in those states where immigration is much more of a daily reality," he said.

The descendants of earlier immigrants sometimes argue that their ancestors came legally, so today's immigrants should be patient and do the same, but it's not a fair comparison, said Michele Pistone, law professor at Villanova University and director of its Clinic for Asylum Refugee and Emigrant services, who is one of the speakers.

"It's hard to say that they came here legally because [at the height of immigration] we really didn't have established immigration laws," she said.

European immigrants faced the same prejudice that Latin Americans do now, she said.

"Villanova University was founded because it was hard for Irish Catholics to get an education anyplace else," she said.

"In the late 1800s, the way they described Italians is precisely the same language they use about Mexicans today."

Today's Latin American immigrants don't come for social services, but to work hard and send much of their money back home, where it outstrips what comes from the U.S. through foreign aid, she said.

The best way for the United States to stem immigration is to work to improve employment, housing and basic political and religious freedom in nations that immigrants are fleeing, she said.

"In Catholic social teaching, it is fundamental that people migrate because they want to provide for their family. If they can't provide for their family in their home nation, that doesn't mean they shouldn't have the right to move," she said.

Refugees from the Middle East, particularly Christians, still try to come here to flee violent persecution and severe economic discrimination, she said.

"We have a country that was created as a haven for people fleeing religious intolerance, and Pennsylvania was founded on the principle that people should have a place to flee from religious intolerance," she said.