The problem with Mormonism is that you have to parse a sentence like that very carefully. For instance, Mormons do believe that Christ is the Son of God, but not that He is God. They believe that He was created. I support Romney, but I keep that very distinct from supporting Mormonism, which I cannot do.
And what exactly does that have to do with electing the President of The United States of America?
We have no problem with calling Christ God, and we believe that Christ was begotten of the Father in the beginning as a spirit, then later begotten in the flesh as the Son of God.
But, as has been pointed out, it makes no difference as to being a good POTUS or not.