But while I was leaning in the Democratic direction, I was fully aware that the Democratic Party backs virtually unlimited access to abortion — a position I do not and cannot share.

I knew that, should a Supreme Court vacancy occur when he is in office, Obama would almost certainly appoint a justice who will maintain the court’s historic 1973 decision in the case Roe v. Wade, which struck down the country’s last legal restrictions on abortion. These political realities were, or should have been, quite enough to give Catholics pause before voting for the Democratic ticket. They certainly gave me pause.

The U.S. Catholic bishops had vexed Americans like me in mind when they issued their 2007 guidelines on how Catholics should engage in political life. “Forming Consciences for Faithful Citizenship: A Call to Political Responsibility From the Catholic Bishops of the United States,” as the document is known, insists that Catholic involvement in political culture must be “shaped by the moral convictions of well-formed consciences and focused on the dignity of every human being, the pursuit of the common good and the protection of the weak and vulnerable.”

“Intrinsic evils,” such as abortion and racism, can never be supported, while seeking justice and pursuing peace must always be approved and backed. But the bishops foresee the most common problem for Catholics in the voting booth: There is rarely any candidate whose views either coincide exactly with Catholic teaching or explicitly contradict it in every respect. That would make the decision easy. In the real world, however, “Catholics may feel politically disenfranchised, sensing that no party and too few candidates fully share the church’s comprehensive commitment to the dignity of the human person.”

In considering how to vote under these circumstances, the bishops conclude, “there may be times when a Catholic who rejects a candidate’s unacceptable position may decide to vote for that candidate for other morally grave reasons. Voting in this way would be permissible only for truly grave moral interests, not to advance narrow interests or partisan preferences or to ignore a fundamental moral evil.”

In the end, I decided to vote for pro-choice Obama for what I consider to be “morally grave reasons.” He is the right man to lead America through months, and perhaps years, of hard times, when thousands are losing their jobs and homes and businesses, and are in danger of losing their hope. He is the right man to counteract the poison of cynicism, greed, ignorance and fear that George W. Bush’s presidency has spread throughout American political culture. He is the right man to restore America’s promise and reputation as a force for good in the world. These were serious reasons to vote for Obama in this moment of crisis — one that is moral and spiritual, as well as economic and political — and they were among the reasons I did so.

I am aware that some readers of this column, and many American Catholics, will not agree that I made the right move. A few U.S. bishops even broke with their colleagues and declared that, in their dioceses, “Forming Consciences” did not apply, and that to vote for a pro-choice candidate under any circumstances is wrong. While I respect the opinions of these dissenting bishops and their followers, I believe that the guidelines dealt with the choice Catholics had to make in the most realistic and faithful way possible.

The task now before Catholic Americans is the patient, determined reformation of the political culture, especially in the Democratic Party. In their document, the American bishops wisely advise the following: “As Catholics, we should be guided more by our moral convictions than by our attachment to a political party or interest group. When necessary, our participation should help transform the party to which we belong; we should not let the party transform us in such a way that we neglect or deny fundamental moral truths.”

Advancing such a transformation in public life is a tall order. But it is a project worth every ounce of energy American Catholics can muster.