Republican U.S. Sen. John Thune of South Dakota sought a decisive reelection win Tuesday over his Democratic challenger for a fourth term that could feature a bid to eventually become his party's leader in the Senate.

The 61-year-old Republican held a large fundraising advantage over Democrat Brian Bengs, an Air Force veteran and university professor. Thune is the second-ranking Senate Republican and is seen as a potential pick to succeed Sen. Mitch McConnell once he steps down from leadership.

The most dramatic moment of the campaign for Thune came before it began, when he contemplated retiring rather than running for reelection. He had shown signs of weariness after navigating a Republican Party dominated by former President Donald Trump, who at one point called for a primary challenger to unseat him.

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Once he chose to run, Thune easily fended off a pair of primary challengers in June and has ridden out the campaign season in the heavily Republican state by avoiding most engagements with Bengs.

The quiet election year allowed Thune to amass over $17 million in campaign funds — money that could help line up allies if he moves to become Senate leader.

Sen. John Thune talks with reporters on Capitol Hill in Washington on Jan. 20, 2022. Thune is running for his reelection in the Nov. 8 election. (WHD Photo/Susan Walsh, File)

Only one South Dakota politician has won a fourth Senate term — Republican Sen. Karl Mundt, who held a seat from the 1950s to the 1970s. After voting early Tuesday, Thune said he was "hopeful" he would match Mundt's historic run.

He added that he was "confident" the GOP would gain a Senate majority after Tuesday's midterm elections.

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"I think the momentum has shifted in the right direction," he told The . "We feel really good about where the races are."