(CNN) Someone is lying. Or, at the very least, badly misremembering.

That's the only possible takeaway from the ongoing back and forth between Sens. Bernie Sanders of Vermont and Elizabeth Warren of Massachusetts over whether the former told the latter that he did not believe a woman could be elected president in 2020. And the feud got worse, not better, during -- and after -- Tuesday night's Iowa debate

Asked directly about Warren's statement that Sanders had told her in a December 2018 meeting that he didn't believe a woman could win, the Vermont senator said this:

"Well, as a matter of fact, I didn't say it. And I don't want to waste a whole lot of time on this, because this is what Donald Trump and maybe some of the media want. Anybody who knows me knows that it's incomprehensible that I would think that a woman cannot be President of the United States."

Warren was then asked what her reaction was to what Sanders had said back in 2018. "I disagreed," she said. "Bernie is my friend, and I am not here to try to fight with Bernie. But, look, this question about whether or not a woman can be president has been raised, and it's time for us to attack it head-on."

Read More