Ben Carson was a favorite among practicing Christians, but last month's interview that touched on hell and rapture is hurting him. (Paul Sancya)

When the political press writes the obituary of Ben Carson’s campaign — assuming his recent staff shake-up doesn’t lead to a stunning revival — the retired neurosurgeon’s foreign policy problems almost undoubtedly will be cited as the cause of death.

That might be only partially right, though. Another Carson flub that has flown below the radar is his confusing end-times theology, which he initially tried to explain in an interview with our Sally Quinn in a story that ran Dec. 1.

Here’s the key passage:

He dismisses the “Rapture”  the idea, embraced by many evangelicals, that at some point before the last days described in the book of Revelation, many Christians will literally be, as predicted in the New Testament, “caught up together … in the clouds to meet the Lord in the air.”

Carson doesn’t share that view. “I don’t see any evidence for that in the Bible,” he says.

He also does not believe in hell: “I don't believe there is a physical place where people go and are tormented. No. I don’t believe that,” he says.

Carson told CNN this week that his comments to Quinn were misinterpreted — that what he actually doesn’t believe in is a “secret” rapture and a version of hell “where there’s this dungeon and there’s a bunch of little minions poking people forever and ever.” Clear?

(If backing away from a troublesome Post story sounds familiar, you might be thinking of that time Carson shot down our report that a staff shake-up was coming, only to part ways with his campaign manager and two other advisers one week later.)

To the broader electorate, foreign policy is obviously more important than Carson’s views on hell and the Rapture. And there is no doubt that his sharp decline began when, just four days after Islamic State attacks on Paris in November, the New York Times quoted a top Carson adviser as saying, “Nobody has been able to sit down with him and have him get one iota of intelligent information about the Middle East.” Carson's many interviews on foreign policy have backed up that assertion.

A 17-year-old video surfaced of Republican candidate Ben Carson claiming that the Biblical figure Joseph built the Egyptian pyramids to store food. The Fix's Chris Cillizza explains why this comment will only help Carson's campaign. (Sarah Parnass/The Washington Post)

But Carson’s base isn't foreign policy buffs; it's practicing Christians — people with whom he built a strong affinity over several decades as an outspoken man of medicine and also of God. Count me among those who, as a boy, received a copy of “Gifted Hands” from parents who pointed to Carson as an inspiring example of faith lived out in a highly intellectual, secular profession. I can tell you — personally — that his chief appeal was never about counterterrorism expertise.

What's more, evangelical Christians are an especially huge factor in the first-in-the-nation Iowa caucuses. They represented the best chance for Carson, who has never held public office, to legitimize his outsider's bid for the White House with an early win. Losing these voters would basically end his chances — and he's been losing them quickly.

Source: Fox News polls

The biggest decline, indeed, came after the Paris attacks. It continued somewhat after the Dec. 1 Quinn story. But it's hard to say whether that registered immediately, given that the attacks in San Bernardino, Calif., were the following day — again highlighting national security and foreign policy.

But the theology problems persist for Carson, as the CNN interview suggests. His new campaign chairman, retired Major Gen. Robert F. Dees, tried to smooth things over when he joined the candidate on CNN and assured Christians that Carson is "a man who believes in mainstream doctrine." (Carson is a Seventh-day Adventist, a faith that has in the past been scrutinized by other Christians.)

The trouble is that "mainstream" is a very squishy concept — and that's a big reason why there are so many denominations with different views on things such as baptism (infant or adult?), worship style (contemporary or traditional?) and even which day is the Sabbath (Saturday or Sunday?). As a Seventh-day Adventist, Carson goes with Saturday, by the way.

Two other subjects on which Christians often disagree are what the Rapture will entail (how the second coming of Christ will play out, basically) and what hell is like. The popular "Left Behind" book series — apocalyptic fiction based on one interpretation of the book of Revelation — is a staple in many church libraries and was turned into a movie starring Nicholas Cage in 2014. ("Left Behind" author Tim LaHaye endorsed Mike Huckabee for president on Monday; he also backed the former Arkansas governor in 2008.)

Rather tellingly, Christian news outlets appeared to struggle with how to report on Carson's original comments last month; some of the most prominent publications simply repeated what he said without passing judgment on its accuracy.

Meanwhile, some conservative commentators have cited Quinn's column as the makings — or at least symptomatic — of a serious problem for Carson.

"Talk to people in Carsonland, and they’ll concede some self-inflicted wounds," wrote Byron York of the Washington Examiner, adding: "Who let Carson talk to The Washington Post’s Sally Quinn on the subject of religion? In that interview, Carson said he does not believe in the Rapture, or in the reality of Hell. The campaign had some cleaning up to do with evangelicals after that one."

Christian candidates usually stick to the shared foundation of virtually all denominations — that Jesus is the son of God, whose death and resurrection redeems the sins of all who call him their savior. And they stop there for a reason. Venturing into theological debates only highlights areas where voters might disagree — and on very sensitive and personal subjects.

It’s not easy to know for certain why voters have abandoned Carson, and it’s likely that many have been influenced by a combination of factors, including foreign policy.

But it’s clear that his decision to discuss specific religious doctrine in the media needlessly opened the door for some Christians to say, "Wait a minute; he doesn't believe what I believe."

That's a tougher story for the media to tell than his flubs on foreign policy, but it's completely logical to think it has played a part in Carson's fall from grace. And it surely won't make his comeback attempt any easier.