Political Correctness often discourages discriminating against candidates because of their religions. I believe that kneejerk reaction is due to a conflation of non-voluntary demographics (eg, race and gender) with distinctly voluntary demographics (religion, political party).
If a person's religion tends to be fundamentalist in nature, which is often true for the new, cult religions like Mormonism and Scientology, it should rightly be noticed. It is difficult to tell if a Catholic or a Jew is personally a fundamentalist; some are, some aren't. But Mormonism is so new and so secretive in nature that it is not wise to assume that the individuals involved are rational or will make political decisions based on what non-members would want.
I would never vote for a Republican because I do not believe he would support policies that I agree with. Likewise, I would not vote for a Mormon or another cult member because I would assume he would be following the tenents of his revelatory text in making political decisions. If I had to choose between a Mormon and a Republican (as in Nevada), I suppose I would abstain from that vote.
I do not fear having my religion judged harshly. I have none. It is ironic that as an atheist I would be immediately excluded as a serious political candidate. After all, it is only religions and other zealous groups that consider their ends more important than their means. It is well known that suicide bombers will lie about who they are and will perform acts that defy rational self-interest or long-term positive objectives in order to achieve a heavenly reward. ANY zealous group has members who do the same (reject rational self-interst) every day. It is they that cannot be trusted. After all, how many fundamentalist Christians crave the End Days and actively work toward their fruition?
It's the athiests that care about the world for its own sake. Religionists would just as soon ruin this world as save it; all they want is heaven.