With the state of the race still fluid, the top contenders were all looking for a moment that might help them to distinguish themselves from the field. In the run-up to the debate, much of the media focus was on the apparent breakdown of the de facto nonaggression pact between Bernie Sanders and Elizabeth Warren, with the latter claiming that Sanders had told her in a 2018 meeting that a woman couldn't win a U.S. presidential election. The two clashed over Warren's claim during the debate; Sanders repeated his denial that such an exchange took place, while Warren declined to retract the accusation. Meanwhile, the moderators once again allowed Joe Biden to avoid serious or detailed scrutiny of his record in the Senate, in particular his vociferous early support for the Iraq War.

Bernie Sanders: We have got to take on the fossil fuel industry and all of their lies.

Joe Biden: I would not meet with the supreme leader who said, "Joe Biden is a rabid dog. He should be beaten to death with a stick."