The first time Manchin tried to lead, it didn't go so well.
"I don't know anyone in the sporting and hunting arena who goes out with an assault rifle," he said on Scarborough's MSNBC show, "Morning Joe," a few days after the Newtown massacre. "I don't know anyone who needs 30 rounds in the clip to go hunting."
That was read as support for two ideas that the gun lobby fiercely opposes: bans on military-style assault weapons and high-capacity ammunition magazines. Gun groups got mad. Manchin seemed to back off, praising the NRA and saying he didn't support "a ban on anything."
After that, advocates on both sides didn't trust him much. But on Capitol Hill, powerful Democrats started to look at Manchin as a potential backroom leader.
Senate Majority Leader Harry Reid, D-Nev., said in a statement Wednesday that Manchin "drove this process by building bridges across the aisle while staying true to his principles. He provided a model for all of us for how to get things done, by rolling up his sleeves to work through tough issues and find common ground."
Earlier in the week, Schumer said that Manchin was "a guy who's got principles, but he's practical. And that's what's happening on guns."
And he had friends. Manchin and Kirk had made a practice of inviting colleagues out on the Potomac River in a boat that Manchin owns a small stake in. Their trips from National Harbor, Md. sometimes included 10 or more senators, and a conversation that covered a variety of subjects, including guns.
"I'm doing everything I can to build relationships," Manchin said Wednesday. "The cheapest thing you can do is feed people."
The beer also helps.
"What happens on the Black Tie stays on the Black Tie," Kirk told reporters Wednesday, in his most expansive exchange with reporters since he had a stroke in January 2012. "Sometimes alcoholic beverages may be served and ties might get loosened. I'd say that Joe has lots of the credit for this."
This spring, Manchin began trying to find a friend who would agree with him about strengthening gun laws. He worked with Sen. Tom Coburn, R-Okla., but they couldn't reach consensus.
When Coburn backed out, Toomey came in. Their deal on Wednesday provides some elements that gun-rights groups will like, including a provision that allows gun owners on road trips to carry their weapons through states where the firearms are not legal.
"So far, I'm going to give him the benefit of the doubt," said Gary Bailey, president of the West Virginia State Rifle and Pistol Association, who spoke with Manchin about the deal on Wednesday morning. He said Manchin had told them he was the right person to broker a fair deal: "He said, you know, 'Something has to be done. So, who's going to do it?' "
The deal also won approval from Schumer, who is on the opposite side of the country's long battle over gun laws. On Tuesday afternoon, as the Senate broke for lunch, Manchin and Schumer huddled in the well of the Senate chamber, even as aides turned off the lights. Later that night, the two met at Scarborough's birthday party, held across the street from the Capitol.
Senate aides said Manchin had a delicate request: Schumer, a love-him-or-hate-him icon of the left, should stay away. Schumer said yes. For Toomey, it was better politics to be seen with just Manchin.
"We have an agreement," Manchin said when the two appeared alone Wednesday morning. "Pat and I have an agreement."