SAN FRANCISCO — John Delaney's address at the California Democratic Convention Sunday was drowned out by jeers after he criticized "Medicare for all."

"What we need as Democrats is to build an economy that works, but it's got to be with smart policies. 'Medicare for all' may sound good, but it's actually not good policy nor is it good politics. I'm telling you," the former Maryland congressman and presidential candidate told the gathering in San Francisco to sustained boos from the crowd. "We should have universal healthcare, but it shouldn't be the kind of healthcare that kicks 150 million Americans off their healthcare. That's not smart policy."

Delaney's remarks, which followed an appearance by Sen. Bernie Sanders of Vermont, were then cut short as music played, signaling that his allotted time had concluded. The term "Medicare for All" is a Democratic branding slogan for a government-financed healthcare system.

[Opinion: What's the matter with 'Medicare for all']

"I have spent my whole life bringing people to together, and I promise to always tell the truth and restore a sense of decency and morality to the office of the presidency, which I think will be on the ballot in 2020," the former businessman said earlier in his speech. "I stand here before you as someone who does not believe that ideology or partisanship or slogans posing as policies are what hard-working Americans need."

"We’ve got to be able to have a robust policy debate out in the open, that’s what this primary process should be about," Delaney said in a statement released later. "A few boos aren’t a big deal, making a really bad mistake on healthcare is ... I have a universal healthcare plan that guarantees everyone a basic government healthcare plan as a right, but also allows people to have options and doesn’t make private health insurance illegal."

His campaign spokesman, Michael Starr Hopkins, was less delicate.

“The Democratic Party is a big tent party with a range of viewpoints. What we saw in San Francisco, while not surprising, was certainly disappointing," Hopkins said in his own statement. "If Democrats think shouting down our own candidates is the path to beat Trump, it’s going to be a long primary season. We need a battle of ideas, not a circular firing squad. We as a party are better than what we witnessed today.”

The audience's response earned a rebuke during the proceedings from Alexandra Gallardo-Rooker, the California Democratic Party's acting chairwoman.

"We were doing really well yesterday, and I know we're not going to agree with everybody," Gallardo-Rooker said. "If you want to scream, please leave."

Former Colorado Gov. John Hickenlooper was greeted with a frosty reception on Saturday when he issued a warning that the party risked alienating moderate voters by turning toward socialism.

"If we want to beat Donald Trump and achieve big progressive goals, socialism is not the answer," Hickenlooper said as the crowd booed. "If we’re not careful, we’re going to end up helping to reelect the worst president in American history."

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