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The Democratic Party primary continues in six states today, but former vice president and front-runner Joe Biden is showing no signs of reaching out to his party’s left flank on one of its signature issues.

On the eve of primaries in Michigan and five other states, where he could all but clinch the nomination with a good performance in the Midwest, Biden sat for an interview with MSNBC’s Lawrence O’Donnell. Biden was presented with a hypothetical scenario: If he were president and a compromise version of Medicare for All came to his desk, would he veto it?

“I would veto anything that delays providing a security and certainty of healthcare being available now,” Biden responded. “If they got that through by some miracle, or there was an epiphany that occurred, and it passed, then you’ve got to look at the cost. I want to know how they found the $35 trillion. What’s that doing? Is that going to significantly raise taxes on the middle class, which it will. What’s going to happen?”

Biden has frequently argued against Medicare for All, based on the principle that people would be forced off their employer-provided healthcare plans, and has implied that they would lose their insurance during the transition to a universal plan. Sanders has maintained that his bill would leave no one uncovered for any amount of time.

"The Vice President is committed to delivering more U.S. Senate and House victories for Democrats — but even with those victories, the chance of Medicare for All passing through both chambers any time soon is close to 0," a spokesperson for Biden's campaign told VICE News. "Our opponents do not speak for us and should never be allowed by the press to put words in the Vice President's mouth. He did not say 'veto.' He made clear that his urgent priority is getting to universal coverage as quickly as possible and he explained why he firmly believes our approach should be to build on the profound benefits of the Affordable Care Act with a Medicare-like public option."

The Sanders campaign did not immediately respond for comment.

“Look, my opposition isn’t to the principle that we should have Medicare. Healthcare should be a right in America,” Biden said. “My opposition relates to whether or not, a, it’s doable, and 2, what the cost is and what the consequences for the rest of the budget are.”

“How are you going to find $35 trillion over the next 10 years without having profound impacts on everything from taxes for working and middle-class people, as well as the rest of the budget?” he added.

A study by the libertarian think tank Mercatus that Biden's cited frequently in the primary debates, said that Sanders’ plan would cost $32 trillion over the course of 10 years. An analysis by the left-wing think tank People’s Policy Project, however, found that the plan would save over $2 trillion in national health care expenditures.

Biden’s opposition to something resembling single-payer hasn’t always been so fierce. A clip from his 2007 campaign that made the rounds last week shows Biden — then making his second bid for the presidency — telling a voter that the country could have a “universal” Medicare plan that covers everyone from birth. “We can afford to do that,” Biden said at the time.

“What happened?” Sanders policy advisor Alex Jacquez asked in a tweet.

While Biden is the odds-on favorite to win the primary, Sanders has succeeded in popularizing Medicare for All among Democrats. In every state that has voted so far, exit polls have found majority support for the proposal with primary voters.