Senator Lindsay Graham, a Republican from South Carolina, took on the toughest challenge of his career on Tuesday, prompting a Democratic comeback backed by a record-breaking attack of campaign money to win a fourth state, according to the Associated Press.

The victory reassured the tense Republicans, who this fall were forced to divert tens of millions of dollars from the main battlefields into an ultra-conservative nation to save Mr. Graham. It also dashed the hopes of Democrats who believed that a victory for their candidate, Jaime Harrison, would improve their chances of grabbing the majority in the Senate.

Mr. Harrison, a black Democrat whose start-up campaign carried a boost to progressives across the country, was the second African-American elected to the Senate since Reconstruction.

In the end, however, Mr. Graham, chair of the influential Judicial Committee, relied heavily on his standing in Washington to advance. A few days before the election, he helped achieve a unique victory for the Conservatives, installing Judge Amy Connie Barrett on the Supreme Court, using party fighting in the Senate to bolster his campaign. He also benefited from a close relationship with President Trump, who easily led the country on Tuesday.

“To those who follow this race from afar, I hope you get the message,” declared Mr. Graham the Victor Tuesday night in Colombia. “This is the message I received: People love what I do, and I’ll keep doing it.”

He added, “When it comes to Lindsey Graham and the Graham team, the best is yet to come.”

Mr. Graham, 65, has been a staple in Washington since the 1990s, when he was first elected to the House of Representatives, and is known to be an intelligent and effective political messenger.

He avoided making his fight against Mr. Harrison personal. Instead, he attacked his Democratic opponent as a general liberal whose political preferences about health care, spending, and judges simply did not align with the strongly conservative state.

But recent results suggest that Mr. Graham’s standing has also taken a major hit in the state since he was last run in 2014. Before his re-election this time, the senator made a major political shift, sidelining his reputation as a bargainer. Who once described Mr. Trump as a “xenophobic, religious fanatic” to present himself as a conservative warrior standing to the right of the president. The shift appeared to alienate some moderate Republicans who were suspended by the president, even after he failed to convince some of his most conservative supporters.

Mr. Harrison tried to exploit these divisions, portraying Mr. Graham as an ethically hacker politician ready to do whatever it took to win. He has more than $ 86 million in contributions – a record for a Senate race fueled by out-of-state liberals who hated Mr. Graham – Mr. Harrison covered the state with ads that not only boosted his candidacy but also boosted Bledsoe, the Constitution Party candidate who was He hopes to draw the conservative vote away from Mister Graham.

This has not proven sufficient. Mr. Harrison simply couldn’t find enough South Carolina residents to vote for a Democrat.

“Tonight just slowed us down, but a new South with leaders who reflect society and serve everyone’s interests will be here soon enough,” said Mr. Harrison Tuesday night in a concession speech. He urged Mr. Graham to develop his independent streak.

If he had a chance to do so, it almost certainly ended in the weeks after Judge Ruth Bader Ginsburg died in mid-September. In 2018, Mr. Graham’s fiery defense of Judge Brett Kavanaugh against charges of briefly sexual assault made a conservative rock star.

This time, as chair of the Judicial Committee, he had a microphone and lights at nationally televised hearings to present himself as an ally of conservative women and remind party voters of what was at stake. He can credibly claim to be a crucial force in cementing the conservative majority on the court that Republicans have long made a priority.

Now, Mr. Graham will have six more years in Washington. In the weeks leading up to Election Day, Mr. Graham hinted that he might try to regain his independent streak if reelected. With Trump potentially defeated, he will be in a position to play a major role in determining his party’s path forward.