Senators typically loathe the sort of top-down negotiations that produced the deal to lift the debt ceiling through 2024, preferring to use the chamber’s notorious bipartisan gangs that give them more direct input. And this time around only a handful of rank-and-file lawmakers were able to directly influence the process, most distinctly Sinema and Sen. Joe Manchin (D-W.Va.).

The deal was pretty much exactly where the two senators hoped everything would end up — alienating only the far right and left and empowering the center.

“It’s a wonderful deal when you have the extremes back in the minority,” Manchin said.

The two centrist senators barely entered the public debt narrative other than pressing for negotiations. Yet each played an integral role in jump-starting discussions and assembling the particulars of the deal, particularly the legislation’s work requirement, spending and energy provisions.

Sinema leaned on years of relationships with McCarthy and lead negotiators Reps. Garret Graves (R-La.) and Patrick McHenry (R-N.C.) while also consulting closely with OMB Director Shalanda Young and White House counselor Steve Ricchetti, who led the White House strategy alongside Legislative Director Louisa Terrell. She spent Thursday racing around the Capitol, aiding Senate leaders as they sought an agreement to speed votes up, spending literally hours helping craft joint statements and locking in amendment votes.

She got used to playing the hectic role of shuttle diplomacy over the past month. Last week, as Sinema was getting ready to appear on Fox News during a visit to the Arizona border, her cell phone lit up with separate calls within a few minutes from several major debt players: McHenry, Young and Senate Majority Leader Chuck Schumer.

“I was talking with everyone all the time,” Sinema recalled.

Manchin credited Sinema with utilizing friendships from her past life in the House to get things rolling. The former governor had a different lane.

The West Virginia moderate coordinated with centrist Democrats in the House on messaging and spoke to both McCarthy and Schumer about modest ways to rein in spending. He finally got the framework very few in his party wanted just a month ago: some spending restraint, and yes, approval of the Mountain Valley Pipeline.

The two centrists often publicly thwarted progressives’ agenda during the first two years of Joe Biden’s presidency, but most of their work this episode occurred behind the scenes. In some ways it’s a capstone to the two senators’ outsized imprint on government: Though they have other unfinished priorities, the debt limit negotiations may be their top accomplishment during this term’s split Congress — as both consider reelection runs.

Manchin’s public restraint regarding inclusion of the pipeline was intentional: He worried it could poison the provision. He remembers all too well the GOP voting down his energy permitting reform bill after Democrats’ party-line climate, health care and tax bill passed last year.

“For them to go out from the beginning and say, ‘OK, we gotta get this in for Manchin?’ That wasn’t a strategy that I thought would be helpful,” he said in an interview. “Republicans had to be where that’s going to be planted from their side.”

Sen. Shelley Moore Capito (R-W.Va.) called the pipeline’s inclusion in the debt deal a “team effort” and spoke to Graves, McCarthy and others to push for the pipeline. One of Manchin’s potential Senate race rivals, Rep. Alex Mooney (R-W.Va.), voted against the debt deal.

Manchin also advised both Schumer and McCarthy on how they might handle modest budget caps. It didn’t go over well with Democrats at first.

“‘Chuck, don’t you think it makes sense that since we increased spending so much because of Covid ... maybe we should start going back to lower spending rates?’” Manchin recalled telling Schumer. “And he said ‘oh, I know, you’re for it. But nobody else is.’”

In the end, the agreement was far better for Democrats than what McCarthy had pushed. Internally, the White House drew a red line back in February over supporting anything longer than two years of enforceable caps in any budget deal, according to a White House official not authorized to speak publicly, and insisted that any debt limit suspension must be at least two years. Republicans sought a longer budget agreement and a shorter debt ceiling lift.

That wasn’t the only tricky third-rail that the centrist duo helped navigate. Sinema pushed Republicans, telling Graves that Democrats would need something on energy transmission and storage or “the votes will not be there.”

She also informed the White House, which had drawn a hard line on no new work requirements, that McCarthy was going to need something.

“I was like, ‘He’s not going to be able to close the deal without it,’” Sinema recalled telling the White House of McCarthy’s position with House Republicans. “Being able to share that with them allows them to spend some time thinking: What is in the world of the possible?”

The two sides got stuck on the issue of work requirements. White House negotiators consulted Democrats on Capitol Hill and came up with the proposal to expand exemptions to veterans, homeless people and former foster youth, successfully hitting Biden’s requirement that the deal not increase poverty overall.

“Republicans were very insistent, but the president gave us clear direction that we were not going to do something that increased poverty,” said Michael Linden, executive associate director at OMB and one of the administration negotiators.

That helped keep far more progressive senators than Sinema and Manchin on board.

Of course, the White House didn’t keep tabs on every senator. In fact, Sen. Tim Kaine (D-Va.) grew so incensed about the inclusion of the Mountain Valley Pipeline, which would also run through his state, that he let loose on the administration on Wednesday for not giving him a heads up — even as officials had asked for his help with Senate business, like confirming Labor Department nominee Julie Su.

The explosion prompted a call from John Podesta, a senior adviser to the president for clean energy innovation and implementation, in an attempt at damage control. Kaine’s frustration was still evident Thursday as the Senate prepared to vote.

“I’m hoping to have some more discussions with the White House about it because it’s not the way to treat a senator who is a loyal colleague,” Kaine said. He argued he was forced into a position of supporting default or “going back on a promise that I made to all these Virginians that Congress was not going to put our thumb on the scale for permitting.”

Yet the pipeline was a boon for Manchin after his deciding vote for Democrats’ huge party-line bill last year. He acknowledged in the interview that vote “has taken a toll on me in my state” and that part of the reason he hasn’t made a decision on 2024 is he’s able to accomplish far more as an undecided senator. If he were running “I don’t think any of these things would have happened. I’m enough of a suspected target.”

Approval of the pipeline and the provisions speeding up review of some energy projects could change the perception of Manchin’s work: “Maybe that will quell some people saying Manchin didn’t get anything but a pen” from Biden at a signing ceremony, he said.

As is her style, Sinema is less likely to discuss the political implications of legislation or her thinking about running again: “I’m not gonna tell you.” But when asked about liberal Rep. Ruben Gallego’s (D-Ariz.) support for the debt deal as he runs to oust her from her seat, Sinema had a deadpan response.

“Ruben has voted for all of my bills in the last couple of years,” Sinema said. “Which is good. They’re good bills.”