SOUTH BEND -- Far from ignoring the controversy surrounding his visit here, President Barack Obama called Sunday for the opposing sides of the abortion debate to be fair-minded and civil with one another.

Obama, delivering the commencement address at the University of Notre Dame, stressed the need for intelligent, open discourse instead of angry, destructive bickering.

"When we open our hearts and our minds to those who may not think like we do or believe what we do," he said, "that's when we discover at least the possibility of common ground."

The university's decision to invite the 44th president to speak drew the ire of some Catholic groups, who believe Obama's positions on abortion and stem cell research contradict critical church teachings.

The two camps, he said, have views that are often irreconcilable -- though they have more in common than they realize. When those areas of mutual understanding are discovered, he said, it is of great benefit to society at large.

While those for and against abortion may not agree on the issue overall, Obama said the two can agree that it is always a "heart-wrenching decision" for women that has both "moral and spiritual dimensions."

Once that is recognized, he told the crowd of 14,000 at the Joyce Center, the seemingly opposite perspectives can unite, working together to reduce abortions, improve adoption processes and make sure health care policies are based on "sound science and clear ethics."

"Each side will continue to make its case to the public with passion and conviction," said Obama, who received prolonged standing ovations throughout the ceremony. "But surely we can do so without reducing those with differing views to caricature."

Finding places to meet eye-to-eye is imperative, Obama said, given the immense obstacles facing the nation and the world. Since those dangers don't recognize differences between nations or races, the people fighting them can't, either.

"No one person, or religion or nation can meet these challenges alone," said Obama, who received an honorary law degree from the university. "Our very survival has never required greater cooperation and understanding among all people from all places than at this moment in history."

MANY FORMS OF DISSENT, SUPPORT

The signs of differing opinions were visible in many ways Sunday, some more audible than others. Several students adorned their mortar boards with yellow anti-abortion logos, while others bore the red, white and blue Obama emblem from last year's presidential campaign.

Three people were removed from the ceremony for shouting at the president and one man was arrested, according to police. As Obama began his remarks, a man in the upper level of the arena stood and repeatedly shouted "You owe the mother of God an apology." Another screamed that "Abortion is murder. You have blood on your hands."

Some audience members clapped and cheered as Secret Service and police led the men out of the room. When a third person began shouting "You're killing our children," the graduates started a "We are ND" chant that drowned out the jeers.

Obama continued on through the commotion, telling the graduates they should be proud for the way they handled the controversy over the past few weeks.

"I am inspired," he said, "by the maturity and responsibility with which this class has approached the debate surrounding today's ceremony."

'HE UNITED PEOPLE'

Former U.S. Rep. Tim Roemer, D-South Bend, told The Elkhart Truth he was impressed by Obama's "heartfelt" speech, and denounced those who disrupted the proceedings.

"I thought the right-wing zealots hurt themselves by screaming and yelling and not listening to what he had to say," said Roemer, who flew from Washington aboard Air Force One and is Obama's ambassador designate to India.

The president reached out to his opponents, Roemer said, something that is difficult to do given the expansive divide that exists on the abortion question.

"He promised during the campaign that he was going to unite people," he said. "And today, he united people on a very tough issue."

Former presidential candidate Alan Keyes, speaking outside the university's front gate, said Obama's presence has made a new group of "citizen leaders" visible to the public. Hopefully, he said, those people will bring Notre Dame back in line with the church.

"It is a scandalous failure of Catholic education that has brought on this whole mess," said Keyes, whom Obama defeated in the 2004 U.S. Senate race in Illinois.

Notre Dame president Rev. John Jenkins commended Obama for accepting the school's speaking invitation, despite the controversy. It would have been easy to hide from those with opposing views, he said, but Obama's decision revealed his true character.

"President Obama has come to Notre Dame though he knows full well that we are fully supportive of the church's teaching on the sanctity of human life," Jenkins said. "Others might have avoided this venue for that reason. But President Obama is not someone who stops talking to those who differ with him."

'ALL THINGS ARE POSSIBLE'

Obama did not stray from discussing personal faith in his remarks, either. He described the great impact Catholic churches and families had on his life while he was a community organizer on Chicago's south side. Their spirit of cooperation and understanding, he said, was what brought him into the Christian faith.

Yet, despite the intensity with which people connect to values and creeds, there is one universal law that drives all people, Obama said. It is the "Golden Rule," he said, an idea adopted by Christians, Jews, Muslims, Buddhists and humanists.

He charged the 2,900 graduates to live by that ideal, to continually treat others the way they want to be treated. By doing so, he said, true greatness can be achieved.

"When people set aside their differences to work in common effort toward a common good," he said. "When they struggle together, and sacrifice together and learn from one another -- all things are possible."