On Friday the nation marked the 50th anniversary of the assassination of President John F. Kennedy. In the days leading up to the anniversary and over the weekend, newspapers, blogs and news sites ran scads of stories about JFK and what might have been.

Among them was a Washington Post column asserting that Kennedy was not as liberal as people tend to believe today. This led Albert J. Menendez, a writer who worked at Americans United in the 1970s and ’80s and who authored the book John F. Kennedy: Catholic and Humanist, to take issue with that claim.

This debate will go on. Kennedy was in office for less than three years. In the decades since his assassination, he has become something of a blank canvas where almost anything can be projected. What would his foreign policy have been like? Would he have shown more backbone on civil rights during a second term? Was he truly committed to what President Lyndon B. Johnson later crafted as the “Great Society”?

Historians and professors of political science will hash this out. But that does not mean JFK must remain an enigma. There are some things we can say about him with confidence. One is that he was a strong supporter of separation of church and state.

Kennedy’s Sept. 12, 1960, speech to the Greater Houston Ministerial Association is often quoted.

Seeking to allay fears that a Catholic president would take orders from the Vatican, Kennedy asserted,I believe in an America where the separation of church and state is absolute – where no Catholic prelate would tell the President (should he be Catholic) how to act, and no Protestant minister would tell his parishioners for whom to vote – where no church or church school is granted any public funds or political preference – and where no man is denied public office merely because his religion differs from the president who might appoint him or the people who might elect him.”

He added, “I believe in an America that is officially neither Catholic, Protestant nor Jewish – where no public official either requests or accepts instructions on public policy from the Pope, the National Council of Churches or any other ecclesiastical source – where no religious body seeks to impose its will directly or indirectly upon the general populace or the public acts of its officials – and where religious liberty is so indivisible that an act against one church is treated as an act against all.”

But these were not just words. Once in office, Kennedy pursued policies that strengthened the church-state wall. He rebuffed demands from the Catholic hierarchy for taxpayer aid for parochial schools, and he backed birth control programs.

The June 1963 issue of Church & State reported that Kennedy supported federal funding of population control programs overseas. Such programs may seem commonplace today, but they were hugely controversial at the time, with the Catholic hierarchy leading the opposition. Kennedy ignored the clerics and approved the aid.

Kennedy also showed considerable political courage in June of 1962, when the U.S. Supreme Court struck down official programs of prayer in public schools. Polls showed that the Engel v. Vitale opinion was widely misunderstood and very unpopular. It would have been easy for Kennedy to engage in demagoguery.

He did the opposite. Kennedy appealed for calm and reminded Americans of the importance of the rule of law. Speaking at a press conference, he added, “In addition, we have in this case a very easy remedy and that is to pray ourselves. We can pray a good deal more at home, we can attend our churches with a good deal more fidelity and we can make the true meaning of prayer much more important in the lives of all of our children. That power is very much open to us.”

Glenn Archer, the first executive director of Americans United, praised Kennedy for his stands in favor of church-state separation. In his 1982 memoir The Dream Lives On, Archer observed, “His presidency was a golden age for the separation cause, and it was a stirring example of one politician who kept his promises to the people.”

The anniversary of the assassination led many writers to play “what if” games. It’s natural to speculate. If Kennedy had lived and gone on to win a second term, would he have perhaps cobbled together a coalition with enough power to have blunted the eventual rise of the New Right (with its strong Religious Right component)?

We can’t say. But we can say that one of the tragedies of Dallas is that we lost a leader committed to the great American principle of separation of church and state. No national leader who has come afterward has been as powerful an advocate for that protective barrier as JFK was.

We are all much poorer for that.