What's going on here? Is the Constitution being put asunder? Have the candidates stepped over the line? Should they be sent to the locker room for violating the rules of the game?
Absolutely not! What's going on is a healthy, robust discussion about the role of religion in American life. After all, religion is often a powerful influence on one's life. If you doubt that, consider how it has animated the actions of suicide bombers around the world. If an Islamic fundamentalist was running for president, wouldn't you want to know that? And wouldn't you want to know how such a candidate felt about things like the separation of church and state, religious tolerance, and the role of women in society before casting your ballot? Such an inquiry does not amount to an impermissible religious test under the Constitution. Imposing an impermissible test under the constitution would be to say that if you are a Muslim (or a Presbyterian or a Mormon), you cannot run for office.
If what we believe determines how we behave (and it often does), then an exploration of one's religious beliefs is fair game in any election. The electorate has a perfect right to inquire of the candidates about their religious beliefs. They do well, however, to stick to relevant inquiries. How a candidate feels about transubstantiation, concupiscence or infralapsarianism, and whether they are "sippers" or "dippers" during communion is not likely to reveal much about how they will govern. On the other hand, queries about where our rights come from, whether or not human beings are created in the image of God, and whether all people are really created equal (points of view that are often shaped by our religious views) may provide useful information by which to judge the candidates.
In engaging in such inquiries, voters will do well to do so with charity and humility. After all, probing into deeply held views can provoke strong reactions among candidates and the electorate alike. The goal should to be to inform, not inflame. Demagoguery does not advance the democratic process. But to suggest that an inquiry into one's religious beliefs is off limits and irrelevant to the voters' consideration of a candidate trivializes the importance of religious faith and reflects a poor understanding of the things that animate human behavior.