SAN FRANCISCO – Former Colorado governor John Hickenlooper found a way to stand out at a crowded gathering of California Democrats: He denounced “socialism,” and got booed.

“If we want to beat Donald Trump and achieve big progressive goals, socialism is not the answer,” Hickenlooper said at a Saturday afternoon session of the state party’s annual convention. As the jeering grew louder, Hickenlooper added: “You know, if we’re not careful, we’re going to end up reelecting the worst president in American history.”

Hickenlooper’s presidential campaign had previewed the remarks hours before he spoke. The Coloradan, who was a geologist and a brewer before entering politics, has repeatedly argued for Democrats to embrace and reform capitalism.

In a May op-ed for the Wall Street Journal, he wrote that he was “running to save” the “only economic system that can support a strong middle class.”

In an interview, Hickenlooper said he had spoken “inartfully,” and that he did not mean to single out any of his opponents, though Sen. Bernie Sanders, I-Vt., is the only self-identified “democratic socialist” seeking the White House.

“We’ve got to clearly show that we reject socialism,” Hickenlooper said. “We’ve got to do that because Republicans will try to make us into socialists even if we’re not. If we’re not willing to draw a bright line and say we’re not socialists, we could quite possibly reelect this president.”

Some in the audience disagreed with Hickenlooper’s thinking. Jonathan Tasini, a labor activist who endorsed Sanders in 2016 and published a book about the senator’s ideas, said that Hickenlooper had effectively talked his way out of the 2020 race. Hickenlooper had also been booed for saying that Democrats should not “[remove] private insurance from over a hundred million Americans,” a reference to Medicare-for-all legislation.

“Every single presidential candidate came into this hall was treated with respect,” Tasini said. “He red-baited us and got down in the mud, and I think it finished him.”

Hickenlooper’s allies saw it differently, speculating that the cold reception at a convention dominated by liberal activists would help distinguish the governor to moderate Democratic voters. Asked how the booing might play on Fox News, which has devoted hours of coverage to the rise of socialists inside the party, Hickenlooper said it would help.

“I think what it says is that we are having that discussion as Democrats, and my hope is that we will clearly say, a result of those broadcasts, that Democrats are not socialists,” he said.

Other Democrats have taken opportunities to distinguish themselves from the party’s left flank. Sen. Michael Bennet of Colorado, who joined the race last month, told one of his New Hampshire audiences that he had stood and applauded during the State of the Union, when President Trump said that America would “never be a socialist country.”

“I was the first person out of their chair,” Bennet said. “Bernie was right behind me, and he was kind of grimacing . . . [but] what I was trying to do was not allow the president to disqualify Democrats. In my part of the country, when you call somebody a socialist, or when they call themselves socialists, it makes it harder for them to get elected.”