No idea what to expect from Kasich tonight, or whether it'll impact anything, but he does seem similar, to me, to another famous cross-party endorser: Zell Miller, the Georgia Democrat who spoke at GW Bush's 2004 convention

Miller represented a one-time Democratic constituency - moderate/conservative Southern whites - that had been deserting the Democratic Party, and his journey to being a GOP presidential endorser/voter was one that many similar kinds of people had made or would make

Kasich, meanwhile, got his support in 2016 from upscale suburban/highly-educated places, and he lives in the northern Columbus suburbs -- the kind of place where the GOP of Romney was much more appealing than the GOP of Trump

we know from the 2016 demographic voting patterns that plenty of formerly GOP voting suburbanites have already made the same journey Kasich has made - from R to D in prez races. And many more likely will make that journey, like Kasich has, in 2020

the Biden camp is wise to try to find people who can extend olive branches to those realigning voters - just like the GOP was wise to highlight Miller in 2004