While the basic tenets of Mormonism can be criticized, they are not key to the election, any more than Bill Clinton and Jimmy Carter are Southern Baptists.
We all know there's quite a row about Bush's faith, which, theologically, is the same as Clinton's and Obama's. Whatever frailties Romney's theology has, isn't he, in America, free to believe in the god of his choice
re: Some Mormons Worry as Faith Comes Under Scrutiny
Mitt Romney's Presidential Rivals Have Used His Mormon Faith for Negative Campaigning