Mario Cuomo was never the presidential candidate Democrats dreamed of. But the three-term New York governor was long an eloquent spokesman for American liberalism.

"You campaign in poetry," he memorably told The New Republic. "You govern in prose."

And you can be wrong in both.

In 1984, the same year gave Cuomo gave a stirring keynote address at the Democratic National Convention, he delivered a speech at Notre Dame University in which he attempted to reconcile his Catholic faith with his support for legal — indeed, taxpayer-funded — abortion.

The essence of Cuomo's argument was that abortion rights and religious rights spring from the same principles. You can't protect one without defending the other.

"I protect my right to be a Catholic by preserving your right to believe as a Jew, a Protestant, or non-believer, or as anything else you choose," Cuomo said. "We know that the price of seeking to force our beliefs on others is that they might some day force theirs on us."

A fine brief for religious liberty. People who favored banning contraception probably never envisioned a differently motivated government would someday mandate the Little Sisters of the Poor pay for contraceptive coverage.

In practice, though, this argument quickly finds itself in a confusing gray area, as the government already codifies as law the beliefs of many faiths. Uncle Sam outlaws theft even though the Ten Commandments say thou shalt not steal. Homicide is illegal even though the Ten Commandments say thou shalt not kill. Many religions teach us to care for the poor. Cuomo would not argue that social welfare spending therefore violates the separation of church and state.

Religious people were at the forefront of fights against slavery and racial segregation. Banning slavery and segregation may "force our beliefs on others," but it is not necessarily enshrining religious doctrine in civil law.

From a religious liberty perspective, why are these laws different than a potential government ban on abortion?

Cuomo merely observed that the Catholic Church teaches that abortion is wrong, and stopped there. He did not grapple with why the church and other abortion opponents believe the practice is wrong, or address any of the rational justifications for opposition to abortion.

Abortion is different from religious doctrines like sanctification, transubstantiation, or the immaculate conception. It is different from religious truth claims like the parting of the Red Sea, Joseph Smith being visited by the Angel Moroni, or the resurrection of Jesus. It differs even from ethical questions like whether a person should drink coffee or alcohol, engage in premarital sex, or indulge in pornography.

If abortion is the unjust taking of innocent human life, then the reasons for thinking it is wrong are also good reasons to consider getting the government involved.

Most people who oppose abortion may be religious, just as abolitionists were once heavily religious. But you can oppose abortion without believing fetuses have souls just as easily as you can oppose slavery without necessarily believing a would-be slave was created in the image of God.

The overwhelming majority of religious people would grant that not all sins should be crimes. But some sins — theft, fraud, slavery, the killing of innocents — are proper objects of public concern.

Cuomo anticipated some of these objections. "It has been argued that the failure to endorse a legal ban on abortions is equivalent to refusing to support the cause of abolition before the Civil War," he said. "This analogy has been advanced by the bishops of my own state."

Amazingly, Cuomo went on to argue, "But the truth of the matter is, few if any Catholic bishops spoke for abolition in the years before the Civil War." He said that American Catholics were a marginal, mostly immigrant population at the time. Their arguments would have carried little weight with the rest of the public. Getting involved in the politics of slavery might have deepened anti-Catholic sentiment.

He added, "They weren't hypocrites; they were realists."

"It is a mark of contemporary liberalism's commitment to abortion that one of its leading lights should have been willing to support temporizing on slavery to defend it," Ramesh Ponnuru observed in his anti-abortion book Party of Death. "It is a further mark that liberals did not reject, or even take notice of, Cuomo's argument about slavery."

But if you are going to go that far down the road of reducing all moral arguments to arcane theological disputes, it is hard to avoid Cuomo's problematic destination.

Mario Cuomo's Notre Dame speech is remembered as the definitive summation of the "personally opposed, but" position on abortion. With all due respect to the late governor's oratorical skills, that has more to do with people's internal conflicts over abortion than the logical strength of his arguments.