Because of redistricting (West Virginia is an economic backwater and continues losing population), the primary on May 10 features two Republican congressmen going against one another, as well as other Republicans and a couple of Democrats. Senator Joe Manchin though took the unusual step of endorsing one of the Republicans.

Source: The Guardian

Joe Manchin has recorded an ad for a Republican in a West Virginia US House election, in which the Democratic senator trumpets his opposition to Joe Biden’s Build Back Better domestic spending plan.
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A former governor and the only Democrat in major elected office in the state, Manchin has now released a 30-second ad in support of McKinley, who because of redistricting is challenging another sitting Republican, Alex Mooney, in a 10 May primary.

In the ad, Manchin says: “I’ve always said, ‘If I can’t go home and explain it, I can’t vote for it. And that is why I opposed Build Back Better. For Alex Mooney and his out-of-state supporters to suggest David McKinley supported Build Back Better is an outright lie.”