Rick Perry and Mitt Romney were asked during Tuesday's debate for the first time about remarks from a pastor supporting Perry, who said that Mormonism is a "cult."

It lead to a carefully measured response from the two candidates on an issue that is a double-edged sword for both of them.

Romney must tread carefully on his Mormon faith, which a substantial minority Evangelical Christians do not view as a form of Christianity. Perry, likewise, needs to shore up his Evangelical support without alienating centrists and voters of other faiths.

When the statement was brought up, the audience in Nevada, a state with a large Mormon population, booed.

Perry repeated previous statements that he did not agree with Pastor Robert Jeffress's comments and but that Jeffress had the right to express his opinion.

Romney said that he's "heard worse" than Jeffress's comments on his religion, but pointed to another part of Jeffress's comments when he introduced Perry: "That idea that we should choose people based on our religion for public office is what I find to be the most troubling."

When asked to respond to Romney's concerns, Perry repeated that he disagreed with Jeffress and "can’t apologize any more than that."

Romney's reply: "That's fine."