The Notre Dame administration knew it was entering a political minefield. But the intensity of the reaction in the week since Obama accepted demonstrates the depths to which Catholics are divided about how Catholic individuals and institutions should engage politics in a pluralistic society.
Adding to the rancor, the Obama invite comes after an election that frustrated the Catholic right and featured prominent Catholic voices making a case for Obama. Early moves by the Obama White House -- such as lifting restrictions on overseas family planning groups that perform abortions and on stem cell research that destroys embryos -- have prompted some U.S. bishops to challenge the new administration.
"This has sparked something beyond the usual right-left controversy," said David Gibson, a Catholic author of books on Pope Benedict XVI and the U.S. church. "Whether you're for or against the decision to invite him is morphing into kind of an X-ray of where everybody stands in the Catholic church."
On one hand, Notre Dame's overture to Obama is in keeping with the university's record of seeking newly elected presidents from both political parties as commencement speakers. Jimmy Carter, Ronald Reagan and George W. Bush have spoken to Notre Dame graduates months after taking office.
Yet with Obama the outcry was swift and fierce. Protests were launched by the Pro-Life Action League and the Cardinal Newman Society, a conservative Catholic group that monitors Catholic universities and colleges for adherence to orthodoxy on abortion, especially. Some Catholics think that view is too narrow.
The Notre Dame president, the Rev. John Jenkins, has said Obama will be honored as an "inspiring leader" facing challenges from the economy, two wars, health care, and immigration and health care reform.
Jenkins also singled out Obama, the first African-American president, as a healer of racial wounds. That is of special significance at Notre Dame because retired university president the Rev. Theodore Hesburgh, 91, linked arms with Martin Luther King Jr. and served on the first U.S. Civil Rights Commission.
The Obama invitation, Jenkins has emphasized, does not condone or endorse Obama's positions on stem cells or abortion but the visit is "a basis for further positive engagement."
That argument has been assailed by Catholics for whom abortion is of paramount importance.
"Commencement is not an occasion for debate," said Catholic theologian George Weigel, a Pope John Paul II biographer. "Commencement is not an opportunity to set the foundations for a dialogue. Commencement and the award of an honorary degree is a statement on the part of the university this is a life worth emulating."
Most U.S. bishops have not spoken out on the matter, deferring to Bishop John D'Arcy of the Diocese of Fort Wayne-South Bend, who is boycotting the ceremony. Bishop Thomas Olmsted of Phoenix made public a letter to Jenkins labeling the invitation to Obama "a public act of disobedience" to U.S. bishops.
Five years ago, bishops adopted a statement that declared: "The Catholic community and Catholic institutions should not honor those who act in defiance of our fundamental moral principles. They should not be given awards, honors or platforms which would suggest support for their actions."
By inviting Obama, Notre Dame is thumbing its nose at the Catholic church and "forfeited its right to call itself a Catholic university," Ralph McInerny, a professor of medieval studies and philosophy, wrote on the Web site The Catholic Thing.
R. Scott Appleby, a Notre Dame history professor, said the last thing the university wants to do is thumb its nose at any bishop or the church. He said it's important to note that Obama is not a Catholic, and that most bishops have focused on dissenting views of Catholic politicians.
Past Notre Dame invitations have drawn protests as well, said Douglas Kmiec, a Catholic law professor and former Reagan administration lawyer whose endorsement of Obama last year was controversial. Many on campus viewed Reagan as unsympathetic to the church's social justice mission, he said. When Bush spoke in 2001 about the disintegration of the family, many graduates wore white arm bands to protest the selection.
Kmiec, who taught at Notre Dame for 20 years and supports the invitation to Obama, called it a sign of a mature university and further evidence that religion is now firmly part of the public discourse.
"Religion has been invited into the public square," Kmiec said. "Our voice is being heard. But we now will presume to exclude from the religious venue the public voices that have the duty and responsibility to people of many different faiths and no faith at all? That seems to be an ironic way to return a favor."
Other Catholic campuses have been roiled by controversies over commencement speakers. In 2007, President George W. Bush's commencement address at St. Vincent College, a small Catholic school in Latrobe, Pa., triggered protests over the Iraq war, which was opposed by the Vatican and U.S. bishops.
This year's scheduled commencement speaker -- U.S. Sen. Robert Casey, D-Pa. -- canceled last week without explanation. Some Catholic conservatives have criticized Casey, who opposes abortion, for his positions on federal funding of contraception and legalization of same-sex marriages.
On the Notre Dame campus, where crucifixes hang in classrooms and more than 80 Masses are said every week, the Obama invitation is generating a range of responses.
"I don't think you have to cut yourself off from everyone who disagrees with you," said Cathleen Kaveny, a Notre Dame professor of law and theology who served on the Obama campaign's Catholic advisory committee.
"President Obama will see a wonderful graduating class of people who are supportive of his agenda of the common good and supportive of affirming the dignity of every human being, but who also want to say to him 'We want to extend that to another class of people -- those who are not born."'
Most students are excited Obama is coming, and some are embarrassed by "the idea that Notre Dame is a radical place and that everyone is up and arms, when it's not," said Gavin Payne, a senior from Seattle.
"Commencement addresses are supposed to be optimistic: 'Go out in to the world and do good,"' said David Wilbur, a senior accounting major from Washington, who opposes abortion but supports the university's invitation to Obama. "He's not coming here to change us or try to make us be pro-choice."
Even among students staunchly opposed to the Obama invitation, there is angst. Greer Hannan, executive editor of the Irish Rover, an independent Catholic student newspaper, thinks the image of an abortion rights supporter dressed in Notre Dame doctoral robes standing next to the university president will not promote dialogue but rather honor positions in conflict with core Catholic teaching.
At the same time, Hannan worried that third-party groups will use the controversy to promote partisan political agendas and do it "in bad taste," using tactics like graphic posters of aborted fetuses.
"Here at Notre Dame we truly have an integrated understanding of respect for life and social justice -- respect for life at all stages," said Greer, a senior from nearby Mishawaka, Ind. "Some of these groups call themselves pro-life but in ways that are exclusive to other marginalized groups in our society."