Twenty-two of Joe Biden’s rivals on Saturday tried to make the case that he’s not the best choice for 2020, mostly without mentioning his name.

Online, critics were less decorous.

Former Alaska Sen. Mike Gravel, one of just two Democratic candidates who skipped the South Carolina Democratic convention, lambasted Biden as “unchanging, unapologetic, unaware” for

Biden’s recent comments praising his own work with segregationist Senate Democrats in the 1970s.

Gravel tweeted that the former vice president “is a disaster waiting to happen. If you are serious about beating Trump, you need to be serious about beating Joe and giving us a serious progressive for the White House.”

Meanwhile, in Columbia, SC, candidates tried to steer the conversation around the front-runner.

California Sen. Kamala Harris entered the convention with a drum line playing as she rode down an elevator. She attacked Trump for everything from his tax and trade policies to an alleged lack of civil rights protections for marginalized Americans. She said Trump’s economic proposals help the rich and hurt farmers.

“We need somebody on our stage, when it comes to that general election, who knows how to recognize a rap sheet when they see it and prosecute the case,” said Harris, a former prosecutor.

Harris added that Democrats shouldn’t “turn back the clock” and instead “start the next chapter,” a veiled swipe at Biden.

Massachusetts Sen. Elizabeth Warren pitched her progressive policies as an agenda that can draw both Democratic and Republican votes.

“People across this nation understand it is time for big, structural change in America,” she said. “The time for small ideas is over.”

Vermont Sen. Bernie Sanders, meanwhile, pushed back at a centrist Democratic group, Third Way, that’s been critical of him, saying his leftist agenda can win the White House.

“We defeat Trump by running a campaign of energy and enthusiasm that substantially grows voter turnout . . . in a way we have never seen,” he said.

Sanders was criticized online for bringing a cadre of African-American aides and supporters onstage with him. The move was seen as an attempt to pander to the state’s large population of black Democrats.

Mayor de Blasio spoke after drawing just 15 people at a breakfast event.

While much of the day’s focus was on Biden, de Blasio’s mind apparently was stuck in 2016. His target of choice was Hillary Clinton.

“I want to be the president of working people,” he said. “Lets be real: In 2016, too many Americans weren’t sure this party was on the side of the working people.”

With Wires