"I, like you, am a member of we, the people, and we know that our country is headed off the cliffs," Carson said at the CBS News 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."
It was an impactful call out to Soviet Russia's threatening the fiber of American life, but the online hoax debunking site Snopes.com notes there's no evidence Stalin ever said the line.
The language praising America doesn't sound like something Stalin would have said, the site said, and it hasn't found any verifiable source for the quote after searching collections of Stain's writings, interviews, and speeches.
Here's the Facebook meme where the fake line originates, via Snopes: