WHEN Pope John Paul II arrives in New York tomorrow, hundreds of thousands of Roman Catholics will enthusiastically flock to his masses. TV crews will fight for position to get good shots of the ''Popemobile.'' And politicians will hail the pontiff as one of the world's great peacemakers.
But behind his personal popularity and the hoopla, the pope arrives in the United States at a time when the church and its theologians are deeply divided.
''American Catholics are overwhelmingly alienated from the Vatican,'' says Randall Balmer, a professor of religion at Barnard College in New York. ''The credibility problems of the church are immense on gender and sexuality,'' he explains.
For example, there are now many Catholics who believe that women should be ordained as priests, that male priests should be allowed to marry, and that birth control is acceptable. ''The church is losing its credibility because of its position on birth control and women - it is a case of men defining how women make decisions,'' says Michael Crosby, a Milwaukee Capuchin Franciscan priest and author of the book, ''The Dysfunctional Church.''
The pope's packed, five-day schedule will include appearances in Newark, N.J., New York City, and Baltimore. He will also address the United Nations during its 50th anniversary celebration.
Disenchanted Catholic theologians don't expect, however, that the pope's fourth visit to the US will pull the church back together. ''If the holy father came to America and announced that he was going to resign for reasons of health, you would find a lot of Catholics very pleased,'' says Richard McBrien, an author and theologian at the University of Notre Dame in Indiana.
A recent Time-CNN poll found that 83 percent of US Catholics are happy with the pope, but only 15 percent think they should always follow his teachings on moral issues such as birth control and abortion.
But many of America's 60 million Catholics still view the pope as a great man, a superstar. Able to attract some of the largest crowds in modern history, the pontiff has been Time magazine's Man of the Year. He was instrumental in the weakening of the Warsaw Pact.
''There is an overwhelming outpouring of love'' for him, John Cardinal O'Conner, archbishop of New York, said last week. Even if an individual disagrees with the pope, he says, ''there is a great respect that he stands for something - he's one of the great moral leaders of the world.''
Lisa Sowle Cahill, a professor of theology at Boston College, believes the pope has been a strong advocate internationally for women. ''His stances on dignity and rights of women are challenging and prophetic in many circumstances,'' she says. But she admits the lack of equality for women in the Catholic church ''makes some people unhappy.''
CONSERVATIVE Catholics dismiss their church's critics, though. Mr. McBrien is a progressive so far out on a limb, ''he can hear it being sawed off,'' says Michael Novak, author and scholar at the American Enterprise Institute in Washington. ''The progressive church is withering here,'' he adds.
McBrien, however, sees progressives as being backed into a corner by a hard-line ''take no prisoners'' papacy. He points to the pope's appointment of bishops over the last 15 years. Almost all of them have been conservatives who absolutely follow the Vatican's directives. ''So many are considered terrible,'' says McBrien who complains that there is a ''growing gap between the hierarchy and the average Catholic.''
But because of the appointments, Balmer says the pope's influence will extend into the next century. Conservative cardinals are likely to elect a conservative pope next. ''When the history of the papacy is written, Pope John Paul II will have his own chapter,'' he says.
While Catholic theologians argue over the state of the church, New York prepares for the papal visit. The church has given 100,000 tickets for the pope's mass in Central Park and 72,000 tickets for his mass in Queens. To protect visitors, the government has trained hundreds of other governmental workers in security procedures.