Stanford Professor of Politics Shanto Iyengar speaks to SBS about the role of religion in the Republican primaries, after Mitt Romney's Mormon faith was decried 'a cult' by an evangelical supporter of his main challenger, Texas Governor Rick Perry.
"The Republican primaries are controlled by the Evangelical wing of the party. Evangelicals make more than 40 per cent of the primary electorate, and of course, a Mormon religion in the eyes of Evangelicals is not a mainstream Christian Church," Mr Iyengar told SBS.
"This is a recurring issue with the Romney campaign and it's going to play out again in the Primaries season".
The supporter who made the "cult" comment, Reverend Robert Jeffress, had introduced Perry at a convention of social conservatives as "a genuine follower of Jesus Christ."
The next day Jeffress did not shy away, insisting to CNN that "evangelicals have a right to select a competent Christian over a competent non-Christian."
Perry quickly distanced himself from the remarks, saying he did not see Mormonism -- also the faith of longshot candidate Jon Huntsman, the former governor of Utah -- as a cult.
But he clearly sees Christian backing as crucial, having rallied thousands in prayer in August at a Texas stadium as he sought to burnish his credentials among religious conservatives.
Americans have always had a Christian president, and until Barack Obama, they've always been white.
Mormonism, which originated in the 1820s in western New York state, is controversial because it fuses Christian theology with teachings that some religious scholars feel are not consistent with standard Christian doctrine.
Watch the interview on YouTube: