Joe Manchin wants to mobilize the middle of the country. What does that even look like?

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Days after celebrating the reelection of a moderate governor in the red state of Kentucky, Democrats experienced hopelessness at the news that Sen. Joe Manchin will not run for reelection in neighboring West Virginia, all but handing that Senate seat to Republicans after next year’s elections.

While US politics can feel paralyzed, the arc of Manchin’s Senate career speaks to an ongoing and never-ending realignment. He came to the Senate with a victory in a 2010 special election, holding the seat for Democrats even though Republicans picked up a six other Senate seats that year – the kind of wave cycle when a Republican could get elected as a senator in Massachusetts and nearing the end of an era when Democrats represented the Dakotas and Arkansas in the Senate.

The idea that either party could pick up six Senate seats in a single election seems crazy today, when only a handful of seats are viewed as truly competitive.

The country and West Virginia changed around Manchin

Just before Manchin arrived in the Senate, there were two Democrats representing West Virginia and two Republicans representing Arizona. Today, Republicans hold every nonjudicial statewide office in West Virginia, except Manchin’s Senate seat, and Arizona voters have elected Democrats to top positions, including US senator and governor.

There’s no guarantee that Manchin would have won reelection in 2024; he barely held on to the seat when he won a second full term in 2018. But there’s a general consensus that the aging politician, who got to the Senate from the governor’s mansion, is the last of a certain breed.

One person who is running to replace Manchin, West Virginia Gov. Jim Justice, dramatically announced he was becoming a Republican at a rally…