Can Joe Manchin Broker a Debt Deal as Republicans Try to Unseat Him?

They included passage of the biggest investment in clean energy in U.S. history, the largest financing of bridges since the construction of the interstate highway system, the first bipartisan gun safety legislation in a generation, a huge microchip production and scientific research bill to bolster American competitiveness with China, a major veterans health care measure, and an overhaul of the electoral system designed to prevent another Jan. 6-style attempt to overturn a presidential election.

While deeply involved in those negotiations, Mr. Manchin often was the voice of “no” within the party, demanding smaller bills and “raising hell,” as he describes it, about the danger of prompting out-of-control inflation. The biggest setback he dealt to Mr. Biden’s agenda was when he killed the president’s sweeping “Build Back Better” domestic policy legislation, a move Mr. Manchin asserts “saved the country from going into a truly hard, hard recession.”

It was ultimately reborn in a smaller form as the climate, health and tax measure and rebranded as the Inflation Reduction Act.

“I know he frustrated some of my colleagues, but I think he played an enormously positive role” in negotiations, including paring down the domestic policy bill, said Senator Mark Warner, Democrat of Virginia. “In retrospect, it was too big. It was basically trying to solve virtually every problem in a single piece of legislation.”

Mr. Warner added: “Let’s face it: The Fed was wrong; most economists cited by the administration were wrong; I was wrong — I didn’t think inflation was going to get as bad as it did — and he was more directionally right.”

Mr. Manchin concedes the current deal-making environment on Capitol Hill will be “more challenging” than in the last Congress, now that Republicans control the House. His vote is also slightly less pivotal, since Democrats have firmer control with a 51-to-49 majority rather than 50-50.

But Republicans and Democrats said Mr. Manchin will still be crucial. Senator Susan Collins of Maine, the top Republican on the Senate Appropriations Committee and an ally of Mr. Manchin’s, says she hopes a group of centrists can figure out how to make deals in the current Congress, just as they did for the past two years.

“There’s going to have to be a lot of give and take and negotiation in order for us to get the people’s business done,” Ms. Collins said. “And Joe will be front and center.”