Jeff Berkowitz, a communications consultant, said statements like Perry’s — accurate though they may be — rub Americans the wrong way because they call that guarantee into question.

“The reason it’s so controversial is because it’s so exactly true,” Berkowitz said. “The more you expose the uncertainty, the more people become concerned about the safety of their investment.”

Daniel Indiviglio, a journalist at The Atlantic and previously Forbes, writes that Social Security depends on steady growth to keep paying retirees — a steady growth which is not occurring.

“[T]he same could be said of a Ponzi scheme. It’s only when investor growth slows that a problem arises. Of course, this is exactly the problem that Social Security faces: population growth slowed, and now it’s running out of money.”