Joe Manchin double crossed Republicans who thought he was in their pocket. https://www.politico.com/news/2022/07/27/manchin-schumer-senate-deal-energy-taxes-00048325

For those who weren't paying attention at the time, Biden had a massive proposed spending bill called Build Back Better, which was going to be the cornerstone of his plan for recovering from the pandemic. Republicans oppossed it, of course. There were 50 Democratic Senators and 50 Republicans, meaning that spending bills could not get past the filibuster (which requires a 60-vote supermajority).

The bill was split into two parts. One was the Infrastructure and Jobs Act, and the other was the (cynically named) Inflation Reduction Act. The IRA contained some of the sweeping provisions regarding climate change, health care, etc which Republicans were dead set against. The infrastructure act they were okay with on principle, but they didn't want to give the Dems a win. The IRA, due to the type of spending involved, could be passed with just 50 votes under a loophole known as reconciliation.

In late 2021, Manchin and Sinema were making noises about the IRA. Democrats started saying very publicly that they should refuse to pass the smaller but more popular infrastructure act until/unless the bigger IRA was passed. It was starting to look like another broken promise from Democrat administrations: a big, ambitious bill (Build Back Better) gets watered down and stripped of all its best parts and a good but wimpy version of it (infrastructure act) is all that's allowed to pass by Republicans.

Democrats backed down, Republicans passed the infrastructure bill, it looked like business as normal. Manchin publicly pulled support for the IRA and by early 2022 it was dead.

It briefly revived in June of 2022. Republicans had no power to block it, but they threatened to block the CHIPS act unless Democrats backed down again. Once again, Manchin, seemingly a loyal Republican plant, pulled his support and the bill died.

Congress passed the CHIPS act, and hours later on the same day, Schumer and Manchin revealed that Manchin had actually reached out to secretly continue negotiations, and they had a deal, and now there was nothing left for the Republicans to block out of spite, they were gonna pass it. And they did pass it, 51 to 50 with Kamala being the tie breaker.

It was stunning, everyone had written off Manchin as a R in D's clothing, but honestly without him it's very unlikely that we would have gotten all three of those bills passed. Even if we'd passed the IRA, Republicans would have killed one of the other bills out of spite.

Is he a republican?