Brown is a terrifically good candidate and Renacci is a terrifically bad one, but if Democrats fail to take the Governor's race here, then Ohio's position in the national environment from 2016 (11 points to the right of the country, basically) will be confirmed. Saying that Ohio likes Democrats because of Brown is like saying the same of West Virginia because of Heitkamp.
That said, the Governor's race is still pretty high-undecided, especially for this late in Ohio; Cordray could comfortably win by 5 or so, in which case Ohio really is still a Tilts R state. But if DeWine wins -- and he's leading now -- then this is going to start turning into fool's gold for Democrats.
I don't know, what really matters is the margin by which Cordray either wins or loses by. For instance, how is DeWine winning by 1 so fundamentally different than Cordray winning by 1? In analyzing Ohio's partisan lean, there is really no difference.
Well, it also depends on the result in relation to national numbers; DeWine v. Cordray is very much being seen a Generic Establishment R v. Generic Establishment D election in Ohio. In 2016, Trump ran 10 points ahead of his national numbers in Ohio. If the GCB is D+9 (like 538 currently has it) but DeWine wins by 1 (which is the average of current polling), then Ohio's basically cemented itself as 10 points to the right of the country, which is Leans R at least. (Even if Cordray is "actually" up 1 right now, that's still 8 points to the right, which is Leans R).
But the race is also pretty high-undecided; Ohio saw large swings in many parts of the state in 2016, much of the party leadership is close to openly anti-Trump (Kasich likes talking about it; Portman avoids the topic but is also obviously not a fan of the President's); meanwhile much of the Democratic Party leadership is based in areas like Lorain (for Sherrod Brown) or Youngstown (for Tim Ryan) which swung hard toward Trump. Lots of voters in the state aren't sure if they prefer Generic Establishment R or Generic Establishment D; undecideds remain high. If they break toward Cordray and he ends up winning by 5 or something, especially if the GCB is a bit too favorable to Democrats at the height of the Kavanaugh fracas and they only win by like 7, then Ohio is basically still a Tossup/barely Tilts R.
Obviously there's not a lot of difference between DeWine+1 and Cordray+1 practically, though I think the former would discourage national Democrats from continuing to try to play in the state, while the latter would encourage them to do so.
