There is a long tradition of American leaders who believe that religion is so personal it shouldn't even affect their private lives. But this rigid separation between religious conviction and public policy lies outside the main current of American history. Abraham Lincoln's theology, while hardly orthodox, was not his "own private affair." "Nothing stamped with the divine image and likeness," he asserted, "was sent into the world to be trodden on." Martin Luther King Jr. claimed that to find the source of our rights, "it is necessary to move back behind the dim mist of eternity, for they are God-given."

These were theological arguments, not merely rhetorical adornments. But they were also carefully limited.

American political leaders have generally not talked about soteriology -- how the individual soul is saved. In Christian theology, these choices are fundamentally private, and government attempts to influence them are both doomed and tyrannical. American leaders have also wisely avoided the topic of eschatology -- inherently speculative theories about the end or culmination of history.

But religious convictions on the topic of anthropology-- the nature and value of men and women -- have profoundly and positively influenced American history. Many of the greatest advances toward the protection of minority rights, from the abolition of slavery to the civil rights movement, came in part because people of faith pushed for them. And religious men and women made those efforts because they were convinced that all human beings -- not just all believers -- are created in God's image.

So what does this mean for Romney? Many Christians have serious problems with Mormon theology on personal salvation and the nature of history -- disputes that go much deeper than those between, say, Baptists and Presbyterians. These disagreements are theologically important. But they are not politically important, because they are unrelated to governing.

Romney, however, should not make Kennedy's mistake and assert that all religious beliefs are unrelated to politics. What Mormonism shares with other religious traditions is a strong commitment to the value and dignity of human beings, including the unborn, the disabled and the poor. This conviction is unavoidably political, because it leads men and women to act in the cause of justice, not in order to impose their religion, but to protect the weak.

Given this common ground, evangelicals and other religious conservatives should not disqualify Romney from the outset. There may be other reasons to oppose him for president, but his belief about the destiny of the soul is not one of them.