Bernie is very popular in...Ohio.
Lol totally false. Take a look at the 2016 primary map sometime; Ohioans from almost all counties across the state, from Appalachia, from the big cities, from the Mahoning Valley all joined together to vote against him (and it's not like Hillary is very well liked.) Anecdotally, almost no older adults I know like him, and even many young people are like "too liberal" or "he's a socialist" (and these aren't Republicans.) Populism works here, but it's gotta be the right kinda populism. His policies were less an issue than his image/branding (although being anti-fracking doesn't play well in Ohio at all if we're being honest.)
Thank you for saying this. This is why I never bought the idea that he would somehow easily win the industrial midwest in the general election just because both he and Trump are "anti-establishment populists."
(Former) Democrats were switching parties to vote for Trump in the Republican primary. If Bernie was so dang appealing they wouldn't have done that. I'm pretty populist myself and I didn't like him much; he seemed out of touch with Ohio values. I will say 2018 Bernie is much better than 2016 Bernie, but he still doesn't really "get it" even though he has good intentions and is in many ways a positive influence on the party.
Sherrod Brown has fairly similar policies to Bernie but is well liked by a broad variety of people, including many Trump voters. He focuses on jobs instead of free college and he seems like a regular Midwestern guy instead of a coastal elite. People are also convinced he's a moderate even though he's one of the most liberal senators. He strikes the perfect balance between being willing to compromise and work bipartisanly to get stuff done and standing up for his values.
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Now Michigan, idk about them. We're similar in some ways but not exactly the same; they seem a bit less staid and conservative. My wild guess is that Bernie would've done slightly better with white voters there, but that black voter turnout would be so low that he loses there anyway. I could be wrong though. He definitely would've lost Pennsylvania regardless so it's a moot point.