COLUMBUS, Ohio — Rep. Joyce Beatty held off a left-wing challenger and Joe Biden easily won the Democratic presidential contest in Ohio on Tuesday, in a contest delayed and held largely by mail due to the coronavirus pandemic.

On Monday, Ohio’s secretary of state said almost 2 million people had requested absentee ballots and just under 1.5 million had already voted. Only people with disabilities or who are homeless could cast provisional ballots Tuesday; others could drop off absentee ballots at Board of Elections offices.

A key contest was held in the state’s 3rd Congressional District, where Beatty (D), a four-term congresswoman, beat Morgan Harper, a former senior adviser at the Consumer Financial Protection Bureau.

Harper, 36, has been endorsed by Justice Democrats, the left-wing campaign corps that helped elect Rep. Alexandria Ocasio-Cortez (D-N.Y.) and that saw Harper as a star and Beatty as the sort of too-comfortable incumbent who could be vulnerable. It was the latest of several races that pit established Democrats against younger supporters of a Green New Deal and Medicare-for-all.

“The critique of many people, including my opponent, is that some of these ideas are pipe dreams,” Harper said in an interview Monday. “Really? We just greenlit billions of dollars to corporations. Why don’t we get to see some of that investment in our people?”

Beatty had not faced a primary challenge since winning the party’s nomination eight years ago and had spent more than $2 million on this race, more than her past three races combined. Harper raised more than $750,000 for her campaign.

In an interview, Beatty said she had tried to demonstrate “what real leadership is about” during the crisis, advocating for the district and sharing health and voting information. She criticized Harper for running without a long record in the district and pointed out that while Harper worked for the CFPB, the bureau’s former director, Richard Cordray, had endorsed the incumbent.

“I don’t know why someone would come out and make promises that are promises that she can’t keep,” Beatty said. “I’m not going to play a game of who can out-left one another. It’s about who can really stand up for the people and get things done.”

Beatty is now heavily favored to win the general election: The 3rd District, which includes most of Columbus and the suburbs, overwhelmingly backed former secretary of state Hillary Clinton over Donald Trump in 2016, with Clinton taking 67 percent to Trump’s 29 percent.

The Justice Democrats, founded in 2017, endorsed a wide array of candidates in the 2018 midterm elections. In this cycle, it became more judicious, putting resources behind a handful of candidates in safely blue districts. In Texas, Justice Democrats-backed candidate Jessica Cisneros nearly ousted Democratic Rep. Henry Cuellar, while two weeks later activist Marie Newman unseated antiabortion Rep. Daniel Lipinski (D-Ill.).

“We endorsed Morgan because of her career of service, the excitement she inspired in the grass-roots activist community, and because she rejected corporate donations that harm the Democratic Party,” said Alexandra Rojas, Justice Democrats’ executive director. “Like AOC has said, for one of us to get in, one hundred have to try.”

Because of the coronavirus outbreak, both Harper and Beatty were forced to cancel traditional campaigning and focus on getting voters to return absentee ballots. On Sunday, Beatty hosted gospel singers and colleagues from the Congressional Black Caucus to argue that voters needed her experience.

“It would be a big loss for your district if she was not there,” Rep. Cedric L. Richmond (D-La.), the chairman of the CBC, said on the live stream. “When you start talking about Congress, where seniority and effectiveness really matter, she is the one.”

Originally scheduled for March 17, the Ohio primary was abruptly postponed, and Gov. Mike DeWine (R) recommended that in-person voting be rescheduled to June 2. But after a chaotic series of events, the Ohio General Assembly eventually passed a bill setting Tuesday as the date for the vote-by-mail primary. Ohio remains under a stay-at-home order.

Sonmez reported from Washington.