Before you make the claim: As long as Romney doesn't use the presidency to peddle distinctive Mormon false doctrines--and I don't think either Governor Romney did--then his LDS heresy doesn't stop me from voting for him.
You might be wise to learn what mormonism is and how at the level the Romney family is in the SLC lds corporation they have promoted their cult.
But he can still do some good in the civil realm. There are lots of non-Christians who have been good citizens and public servants. And I think he'll be a heckuva lot better at president than Obama.