More than two-thirds of the way into the Democratic presidential debate on Tuesday night, former Vice President Joe Biden took a casual swipe at his rivals without specifying whom he was speaking about exactly.

“We can’t be running any vague campaigns. We’ve got to level with people,” Biden said. “I’m going to say something that is probably going to offend some people here, but I’m the only one on this stage who has gotten anything really big done.”

When a CNN moderator pressed Biden to clarify which candidates he thought were being vague, he pointed first to his left at Sen. Elizabeth Warren (D-Mass.) and then to his right, at Sen. Bernie Sanders (I-Vt.), claiming they were both obfuscating about the cost of “Medicare for All.”

What happened next was the most direct and contentious exchange among the three candidates ― the septuagenarian trio leading in the public polls ― thus far in the primary. Sanders and Warren both took Biden to task for what they argued were either policy mistakes that hurt ordinary people or exaggerations of his role in the passage of positive reforms.

Sanders began by seizing on Biden’s insistence that he alone had shepherded “anything really big” into law. He drew a no-holds-barred contrast with Biden’s record on war, trade and bankruptcy reform, aiming to expose him as a false populist.

“Joe, you talked about working with Republicans and getting things done. But you know what you also got done? And I say this as a good friend ― you got the disastrous war in Iraq done,” Sanders said. “You got a bankruptcy bill, which is hurting middle-class families all over this country, you got trade agreements, like NAFTA, PNTR with China done, which have cost us 4 million jobs.”

Sanders and Biden subsequently had a brief back-and-forth about Medicare for All, with Biden insisting that adopting a single-payer system was not necessary for achieving universal coverage.

Then it was Warren’s turn to answer Biden’s implicit charge that she is vague and impractical. She focused on her brainchild: the Consumer Financial Protection Bureau, part of the Dodd-Frank Wall Street reform law.

“Following the financial crash of 2008, I had an idea for a consumer agency that would keep giant banks from cheating people. And all of the Washington insiders and strategic geniuses said, ‘Don’t even try because you will never get it passed,’” she recalled. “And sure enough, the big banks fought us, the Republicans fought us, some of the Democrats fought us. But we got that agency passed into law.”

Warren promised to leverage her knowledge from that fight to use every lever in her power as president, including executive actions, to enact “structural reform.”

“I know what we can do by executive authority, and I will use it,” she said. “In Congress, on the first day, I will pass my anti-corruption bill, which will beat back the influence of money and repeal the filibuster.”

Biden tried to share in the credit for passing the law that created the CFPB.

“I agreed with the great job she did, and I went on the floor and got you votes. I got votes for that bill!” he declared. “I convinced people to vote for it, so let’s get those things straight, too.”

Warren wasn’t having it.

“I am deeply grateful to President Obama, who fought so hard to make sure that agency was passed into law, and I am deeply grateful to every single person who fought for it and who helped pass it into law,” she responded, notably omitting Biden’s name.

Amanda Terkel and Molly Redden contributed reporting.