It is expedient to reason that Carson could be the other side of the Trump coin: a first-time candidate who has jumped in the polls by eschewing political correctness and appealing to Republicans’ hunger for an “outsider” candidate.

That explanation holds water but is also somewhat reductive, glossing over the following Carson has built and cultivated among religious conservatives, his motivational speaking talents, and his compelling personal narrative. Some Republican strategists see parallels with Mike Huckabee’s 2008 campaign for president, which also drew strength from a committed base of evangelical voters.

But Carson’s supporters, as judged by the crowd at a rally here Wednesday, don’t seem to fit any well-worn GOP mold. Many said they backed Mitt Romney during the 2012 Republican primary. They are surprisingly diverse; they are steeped in Carson’s literature and avid students of his story; they are people who have not been involved in politics before.

“We’ve never campaigned for anybody,” said Linda Miller of San Diego, whose husband, Ed, gripped a freshly signed copy of Carson’s book “One Nation.” Both were captivated by his 2013 speech at the National Prayer Breakfast and have signed on as volunteers for his campaign. “We are actually going out and supporting him, not just voting.”