Though I'd nuance some things differently than Gerson, I'm inclined to think he's on the right track here:
Note that this analysis echoes that of Frank Beckwith who who argued against the "Kennedy Mistake" (when someone makes the "claim that his theology and church do not influence or shape his politics"). Beckwith's review of Hewitt's book concluded: "If one does not support Romney’s candidacy, it should not be because he is a Mormon. It should be because one has good reason to believe he is not the best candidate for the office. That is the message of Hewitt’s book. It is one that would resonate with Martin Luther, who once tersely said, 'I’d rather be ruled by a competent Turk than an incompetent Christian.'"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.
Collin Hansen recently interviewed Romney for CT regarding evangelicalism, Mormonism, and the role of doctrine for a politician. Look for it in the September issue.