Believing in this civic faith is the real "religious test" in American politics; it's impossible to imagine anyone being elected president who doesn't profess it. Romney argued that demanding anything more of a presidential candidate is basically un-American. In a passage invoking shunned religious dissenters Ann Hutchison, Roger Williams and Brigham Young, he placed Mormonism in the tradition of once-exotic faiths in America that have been absorbed into the mainstream precisely because our civic religion is so broad and open.
Romney had his slips. It's not true that it would violate the Constitution's prohibition on religious tests for office if a presidential candidate talked in detail about his faith and people voted on that basis; people can vote for or against candidates for whatever reason they like. Romney seemed to contradict himself by not wanting to get into doctrine but still going out of his way to say he believes that Jesus Christ is the Son of God.
But overall Romney dealt with a complex topic admirably. At bottom, all that Romney asks is something very basic -- that he be judged on his merits as a businessman, father, governor and presidential candidate.
In the conclusion of his speech, Romney talked of the difficulty of settling on a prayer at the First Continental Congress in 1774 because of all the different faiths represented there: "Then Sam Adams rose, and said he would hear a prayer from anyone of piety and good character, as long as they were a patriot." Amen.