Imo he and Conor Lamb are the only two plausible Democratic VP nominees from PA (well, Wolf is too, but I just think he's too old), so that's worth something, at least.
Instead of Casey, I'd actually make the list: Lamb, Fetterman, and Shapiro. Fetterman could help the Democratic party salvage their ancestral vote in the rust belt, and I've heard through the grapevine that the PA Dems want AG Shapiro to challenge Toomey in 2022 so he could gain some legislative experience before becoming a potential contender in the future.
I'd prefer Lamb to lambaste Toomey.
Unless Trump loses re-election, in which case Toomey will probably win re-election.
