• Former Vice President Joe Biden slipped up during Thursday night’s Democratic primary debate, referring to one of his close rivals for the party’s presidential nomination, Bernie Sanders, as “the president.”
  • Sanders and Biden clashed over healthcare policy during the debate.
  • “For a socialist, you’ve got a lot more confidence in corporate America than I do,” Biden quipped, challenging Sanders over claims his plans would reduce healthcare costs.
  • Visit Business Insider’s homepage for more stories.

Former Vice President Joe Biden slipped up during the Democratic debate Thursday night, accidentally referring to one of his close rivals for the party’s presidential nomination, Bernie Sanders, as “the president.”

“If you notice, nobody’s yet said how much it’s going to cost the taxpayer,” Biden said while discussing Sanders’ signature “Medicare for All” proposal. “I hear this, large savings, the president thinks – my friend from Vermont thinks – that the employer is going to give you back if you negotiated as union all these years, got a cut in wages because you got insurance, they’re going to give back that money to the employee?”

“Matter of fact they will in our bill,” Sanders responded.

“Let me tell you something, for a socialist you’ve got a lot more confidence in corporate America than I do,” Biden quipped, jabbing at Sanders’ democratic socialist views.

Biden made a similar gaffe on July 31 in the second round of debates, referring to Sen. Cory Booker of New Jersey as "the president," which Biden jokingly corrected to "future president" and then to "senator."

Read more: 7 standout moments from the 3rd Democratic debate

On Thursday night, Biden was attacking Sanders' claim that employers would pay higher wages if they no longer needed to subsidize employees' health insurance.

Biden has positioned himself as a centrist in the Democratic debate over healthcare, pledging to expand the Obama administration's Affordable Care Act. The bill was a signature policy of the administration in which he served as vice president.

Read more: Here are the winners and losers of Thursday's fiery Democratic presidential debate

Sanders has pledged a radical overhaul of the US healthcare system, saying he will expand the federal government's Medicare program to all citizens.

Doing so, he says, will rein in the rising costs of healthcare. Other candidates who back Sanders' plan include Sen. Elizabeth Warren.

On Thursday, Biden focused his attacks on his rivals' healthcare policies.

"How are we going to pay for it? I want to hear tonight how that's happening," he said, with critics claiming their plans would result in higher taxes to fund higher government spending.

Biden, Sanders, and Warren were the three leading contenders to secure the Democratic nomination, according to polls taken ahead of Thursday's primary debate.