WILMINGTON, Del. — Delaware Sen. Christopher A. Coons fended off a left-wing challenge Tuesday, defeating activist Jessica Scarane to win the Democratic nomination for a second full term.

Coons, elected in 2010 to the seat once held by former vice president Joe Biden, has cut a moderate profile in Washington — one that Scarane, a digital strategist and member of Democratic Socialists of America, ran hard against. She endorsed Medicare-for-all and a Green New Deal, suggesting that a suburb-heavy state that has trended toward Democrats could have more liberal representation in Washington.

That message hit a wall with Delaware's Democrats, and Coons outspent Scarane while securing the endorsement of the elected members of his party as well as a strong endorsement from Biden. Coons also said he wouldn't side with Republicans who would block a potential Biden agenda if Democrats won control of the Senate in November. He secured 74 percent of vote to Scarane's 26 percent, with 83 percent of precincts reporting.

"If Minority Leader [Mitch] McConnell — doesn't that sound good? — uses the filibuster to block progress . . . then I'm not going to stand by and watch," Coons said in an interview this past weekend.

Republicans chose a challenger to Coons, with voters backing Trump campaign activist Lauren Witzke, who has tweeted about her belief in the QAnon conspiracy theory, over Jim DeMartino, an attorney endorsed by the state party. Entering the day, Witzke had raised nearly $170,000 to DeMartino's nearly $47,000.

The Delaware contest marked the end of six months of partisan primaries.

Coons, who has derided President Trump and also challenged the Democratic Party’s far left, aired TV spots and distributed mail that emphasized his support from Biden.

It was Coons, who received a master’s degree in ethics from Yale Divinity School, who spoke of Biden’s faith at the Democratic convention nominating the party’s presidential standard-bearer last month, saying, “I’ve known Joe about 30 years, and I’ve seen his faith in action.”

Scarane did not attract the endorsements or fundraising numbers of the year’s major left-wing campaigns, such as New York congressional candidate Jamaal Bowman, who won his Democratic primary race. But her campaign said Monday that it had made more than 900,000 voter contact attempts, reaching most of Delaware’s Democratic voters. It returned to in-person canvassing last month, while Coons’s campaign did not.

The senator outspent Scarane on ads.

“I have an election, and I’m delivering the resources needed to win the election,” said Coons. “I don’t think that says I’m on the run. It says that I’m standing for reelection.”

The senator did not debate Scarane, but the race finished the story of the left’s primary campaigning this year, which unseated three House Democrats and won a string of victories down the ballot. Delaware Democrats control every statewide office and a majority in the legislature, and Gov. John Carney easily beat only a nominal primary challenge.

Republicans, who have not won a statewide race in Delaware since 2014, faced serious disadvantages this year. Their best-known candidate for governor, state Sen. Colin Bonini, ran and lost to Carney by 19 points four years ago; Carney, whose response to the coronavirus pandemic has been popular, was in a stronger position this time. Bonini had five primary opponents, including lawyer Julianne Murray, who was endorsed by the state Republican Party.

Coons was first elected when conservative activist Christine O’Donnell unexpectedly won the party’s primary but then flamed out in the general election after having to insist to voters that she didn’t practice witchcraft. In the Republican race, Witzke, who has tweeted the slogan (“WWG1WGA”) of the QAnon conspiracy movement, outpaced DeMartino 57 to 43 percent, with 100 percent of precincts reporting.

QAnon conspiracy theorists believe that Trump is battling a cabal of “deep state” saboteurs who worship Satan and traffic children for sex. The FBI has identified the movement as a potential domestic terrorist threat.

Lee Murphy, an actor and perennial candidate, won the GOP nomination for the House primary race and will face Democratic Rep. Lisa Blunt Rochester.

Louisiana will hold all-party primaries on Election Day on Nov. 3, and Georgia will hold an all-party primary for the seat held by Sen. Kelly Loeffler (R).