Republican presidential candidate, retired neurosurgeon Ben Carson speaks during the CBS News Republican presidential debate at the Peace Center, Saturday, Feb. 13, 2016, in Greenville, S.C. (AP Photo/John Bazemore)
CNN  — 

Ben Carson referenced a line he said came from Joseph Stalin, a quote that’s believed to have gained prominence as a conservative social media meme, during his closing statement at Saturday night’s Republican debate.

“Joseph Stalin said if you want to bring America down you have to undermine three things – our spiritual life, our patriotism, and our morality,” Carson said, puzzling some observers, who couldn’t quite place the remark.

And for good reason. The mythbusters at Snopes.com, in a recently updated review, state that the line, which Carson is reported to have used before, have little evidence to back up that it came from Stalin. The CNN Reality Check team rated its attribution to Stalin as “false.”

That more familiar version, which quotes Stalin as saying, “America is like a healthy body and its resistance is threefold: its patriotism, its morality, and its spiritual life. If we can undermine these three areas, America will collapse from within,” cannot be found in any of a number of voluminous online libraries, according to Snopes. The oldest account of it, in a letter to the editor of the Lawrence Journal-World, comes from 1983 – three decades after Stalin died.

“We have yet to find a presentation of this quotation that references a verifiable source for it,” the Snopes sleuths write. “Nearly all reproductions of this quotation simply offer it as an undated, unsourced statement attributed to Stalin.”

In an email, the campaign told CNN it was “not sure the actual or original source on which Dr. Carson found it.”

On social media, Carson’s line was met first with curiosity and doubt – then mockery, while conservative writers were immediately suspicious.

The New York Times columnist Ross Douthat asked for a fact check, while National Review senior editor Ramesh Ponnuru wrote, “I do not have to check to know that Stalin quote from Carson is made up.”

Once the dubious provenance of the quote became a point of fun, the jokes came rolling in.

‏Jason O. Gilbert, a writer at Fusion, joked in a tweet, “BEN CARSON: You know, Joseph Stalin once said, ’10 years ago we had Steve Jobs, Johnny Cash, and Bob Hope.’”