The U.S. Supreme Court ended sectarian prayer in public schools and legalized abortion. As a result, many Catholics and other Christians saw themselves surrounded by a hostile culture. At the same time, the global church was opening up to the modern world through the Second Vatican Council, prompting an internal Catholic split over whether the council's reforms were going too far. American Catholics -- better educated and more integrated into American life -- fractured along religious and political lines. Once a solid bloc of mostly Democratic voters, Catholics became swing voters, and Catholic Republicans, a rarity in Kennedy's day, gained influence.
Catholic politicians who supported abortion rights came under more intense criticism from church leaders. American bishops called a vote for legalized abortion cooperation with evil.
On the defensive, these Catholic lawmakers paraphrased Kennedy. They said Kennedy was arguing that even if faith shapes policy, the outcome still had to be acceptable to the wider public. Former New York Gov. Mario Cuomo, a Democrat, in a much-quoted 1984 speech on abortion at the University of Notre Dame, spoke of "the price of seeking to force our beliefs on others." Democrat John Kerry, the party's 2004 presidential nominee said: "I can't take my Catholic belief, my article of faith, and legislate it on a Protestant or a Jew or an atheist. We have separation of church and state in the United States of America."
For conservative Catholics and other conservative Christians these comments were infuriating. Religion should be the source of an unchanging morality that guides all aspects of life, including governing, they argued. Archbishop Charles Chaput, then head of the Denver archdiocese, in a 2010 speech at Houston Baptist University, called Kennedy's address, "sincere, compelling, articulate and wrong."
"His Houston remarks profoundly undermined the place not just of Catholics, but of all religious believers, in America's public life and political conversation," said Chaput, now head of the Philadelphia archdiocese. "Today, half a century later, we're paying for the damage."
Mathew Schmalz, professor of religion at the College of the Holy Cross in Worcester, Mass., said Santorum, who would be the second Catholic U.S. president if elected in November, is among those who believe the church has surrendered too much to the broader culture and has lost its distinct moral voice.
"When Santorum talks about the Kennedy speech that way, he's obviously making a political point about religion and politics, but he's also making a point about Catholic identity," Schmalz said. "Santorum is part of a very vocal constituency among Catholics, but I would say he's still in the minority."