WASHINGTON (AP) — Republican Lindsey Graham has won reelection to the U.S. Senate from South Carolina beating Democrat Jaime Harrison.

Graham on Tuesday faced his most stalwart general election opponent to date in Harrison, a fundraising powerhouse and associate Democratic National Committee chairman who also chaired the state Democratic Party and worked as a lobbyist.

The contest was propelled by an onslaught of spending from both candidates and a slew of third-party groups.

Graham told The Associated Press on Saturday that he also has raised about $100 million, and his third-quarter haul of $28 million represented a quarterly record for any GOP Senate candidate.

Having defeated all previous opponents by double-digit margins, Graham acknowledges, “This is the biggest challenge that I have ever faced,” with some polls showing a neck-and-neck contest.

The astronomic money has amounted to constant digital and broadcast advertising, as well as mailers. Harrison has used some of his copious cash to try to steer conservative voters toward Bill Bledsoe — a Constitution Party candidate who dropped out to endorse Graham, but whose name remains on ballots — in an attempt to cleave votes from the Republican. Bledsoe has asked Harrison to “cease and desist” from what he calls dishonest “dirty tricks” advertising.

The undercurrent of the recent battle over Amy Coney Barrett, President Donald Trump’s third U.S. Supreme Court nominee, has also been a factor. As Senate Judiciary Committee chairman, Graham oversaw that contentious process, where televised hearings kept him in the national spotlight for weeks.

Harrison, meanwhile, had portrayed the 65-year-old Graham as a career politician too far removed from his constituents’ lives.

“It seems like our senator doesn’t understand the dignity of hard work, because instead of working hard for South Carolina, he goes golfing with the president,” Harrison said during a recent Columbia drive-in rally.

Harrison, 44, also highlighted Graham’s previous opposition to election-year high court nominations, including a 2018 video in which he said, “If an opening comes in the last year of President Trump’s term, and the primary process has started, we’ll wait to the next election.”

His reversal after Barrett’s nomination, Harrison has said, means Graham’s “word is worthless.”

Throughout his 25-year Capitol Hill career, Graham has handily defeated primary challengers who accused him of not being conservative enough for the state, where Republicans control both legislative chambers and hold all statewide offices and most congressional seats.

Graham was too conciliatory, critics argued, too ready to work out bipartisan deals. But his burgeoning relationship with Trump has helped elevate his own position with some of those detractors. A group composed of voters from myriad organizations with tea party roots held a press conference to endorse the senator against Harrison, citing anti-abortion issues and Graham’s work to confirm conservative justices as some of their reasons.

More than a million South Carolinians have already voted in this year’s general election, with absentee voting obliterating records from 2016.

Michelle Liu, a corps member for the Associated Press/Report for America Statehouse News Initiative, contributed to this report. Report for America is a nonprofit national service program that places journalists in local newsrooms to report on undercovered issues. Trademark and Copyright 2020 The Associated Press. All rights reserved.