Protestants at the time of the War for Independence and since have talked a lot about the need for a virtuous citizenry to protect this freedom-loving republic. The rhetoric of virtue has always made religion necessary to the health of the U.S. From George Washington to Jerry Falwell, the American religio-political tradition has been to insist on the need for a religious people if this experiment in liberty is to survive.
Although this argument has much common sense behind it, it seems like an argument that any justification-by-faith loving Protestant would steer clear of as much as possible. The talk of virtue, and the assumption that religion makes people good, sounds like a form of works-righteousness. Worse, it sounds like boasting, as if the believers are the good citizens and the unbelievers are the ones we need to keep an eye on.
If Protestants truly took solace in the righteousness of Christ and looked at their own virtues as filthy rags, I think they might be less willing to speak of religion as the basis for republican virtue. They might also consider other ways to preserve civil and political liberty (though I admit this is hard one to reconsider). But with this argument as the basis for political reflection have Protestants merely made America safe for Mormons and Roman Catholics? Have they also given their faith a bad name by coming across to unbelievers as self-righteous?