Rand Paul (52): An ophthalmologist, senator for Kentucky since 2011 and son of congressman and two-time presidential candidate Ron Paul. He was baptised into the Episcopal Church, but now attends a Presbyterian church, where his wife Kelley is a deacon.

"My faith has never been easy for me," Paul said at the 2012 Values Voter Summit, when he took the opportunity to outline his position on numerous issues from a faith perspective. He said his faith had "never been easy to talk about and never been without obstacles." Quoting Dostoyevsky, he said: "I did not arrive at my hosanna through childlike faith, but through a fiery furnace of doubt."

He continued: "I do not and cannot wear my religion on my sleeve. I am a Christian, but not always a good one. I am not completely free of doubts. I struggle to understand man's inhumanity to man," he said, adding that he also struggled with the personal tragedies he has encountered as a doctor.

In his confessional-style speech, he also said that he was "conflicted" about war, saying that good leaders only use force with great deliberation. "I'm not a pacifist, but I do think it unacceptable not to hate war," he said. "I don't think Jesus would have killed anyone, or condoned killing, perhaps not even in self-defence."

One issue he is clear about is abortion – he describes himself as "100 per cent pro-life". On gay marriage, he advocates for the decision to be made at state level. Personally, he opposes it, but said in a recent Fox News interview that he supports the idea of 'contracts' for gay couples with the legal rights of marriage – such as a civil union.

In a CBN video from a pastor's breakfast in March he said that there was a "moral crisis" in America, which has brought about the pressure for gay marriage. But people shouldn't necessarily look to Washington to be the answer, adding "We need a revival in the country. We need another Great Awakening with tent revivals of thousands of people saying reform or see what's going to happen if we don't reform."