What I am writing is a complete guess.
It is not based on unfiltered data. I have not developed any algorithm nor have I done any kind of regression analysis. This is based on gut impressions of material available to the general public and not inside information.
In general, I think Red States will get redder and Blue States will become bluer, with a few exceptions.
The exception, which will probably cost Trump and the GOP the House, is that I think family farmers have been hurt by the tariffs (possibly permanently, supply chains were disrupted badly in some commodities and will take time to recover) and they will likely stay home.
I think the GOP will lose House seats in the farm belt over this and this may be enough to save the seats of Democrats Clare McCaskell in Missouri and Heidi Heitkamp in North Dakota.
The GOP reached an uncommon level of control of statehouses and state capitals between 2009 and 2016 and that control will recede, at least to a degree.
That seems a natural outcome; that kind of progress at the polls is unlikely to be sustained as a general rule. Further, in contrast to 2009 (where the GOP took both the NJ and VA governorships in what proved to be a bellwether event for Obama Years), the GOP lost in both VA and NJ in 2017.
In the Florida governor's race, I think Andrew Gillum will win.
I base this on the fact that Gillum has had at least a slight lead over his GOP rival, Ron De Santis, by most polls---which now seems to be broadening. I think this is significant because there have been allegations of corruption against Gillum as mayor of Tallahassee, which seem at least facially plausible. The trends in the polls imply that this information has been "baked in" and is not dissuading people from voting for Gillum.
Further, I think there is a consensus that De Santis has "played the race card" and that has had a damaging effect on him. Gillum's "A hit dog will holler" comment at the last debate seemed to hit home.
To some degree, that is probably unfair. De Santis's "monkey around" comment, for example, was probably not racially motivated.
De Santis is a fine man. He is a Harvard Law Graduate who volunteered to serve in Operation Iraqi Freedom("OIF") as a Navy Judge Advocate General ("JAG") Officer and was awarded a Bronze Star for his service, an unusually high award for a JAG officer in that Service. He has served in the US House of Representatives.
However, it seems like some Political Action Committees ("PACs") have tried to play the race card (for example, by describing a Rhodes Scholar and Harvard Law graduate as an "LA Rapper"), perhaps based on the belief that this type of attitude was rewarded in 2016. However, the polls indicate this approach may have had dire results for the candidates involved.
This is similar to the situation presented in the race for the House in the New York 19th Congressional District, alluded to above, where the "LA Rapper" ad aired. The incumbent, Rep. John Faso, was NOT behind the ad, it was aired by a PAC, but it has moved Faso from a comfortable lead to "to close to call" to slightly trailing his challenger, Antonio Delgado.
I think it is possible that Ted Cruz will lose in Texas.
Texas is a very Red State, where no Democrat has been elected state-wide since 1994. Ted Cruz, in my opinion, is a principled Constitutional Conservative who believes in the power of the things that built America: free men; free markets; and free pulpits. He is the epitome of the kind of leader Texas . . . and the US . . . really need. I hope he wins.
But here is why I think he might not.
In general, taller, better looking candidates tend to win. O'Rourke is more imposing and charismatic than Sen. Cruz.
Sen. Cruz, a national debate champion at Princeton, is an able and polished speaker. However, O'Rourke puts me in mind of George Burn's quip, "“The key to success is sincerity. If you can fake that you've got it made.”
Sen. Cruz spent 2015 and 2016 running for President. Sen. Cruz is an ambitious man; it would not be fitting if a man of Sen. Cruz's ability were not. However, some may harbor a grudge against Sen. Cruz for running for President as a first term Senator, which may seem overweening ambition. Further, Sen. Cruz, as an able and principled man, has probably made enemies even in the Texas GOP, potentially, enemies with long memories.
It is easy (and, probably, correct) to consider a judge's son named Robert Francis O'Rourke a phony for running for US Senate from Texas as "Beto" O'Rourke. However, O'Rourke is from El Paso, a place, in my experience, where it is hard to get around if you are not bilingual. O'Rourke's mother is from an old Texas family, the Korths. Her father, a lawyer, bank president and former Secretary of the Navy, was an associate of the Suite 8F group of Right Wing Texas Democrats in the 1950s and 1960s.
Sen. Cruz's family came to Texas more recently and settled in Houston.
O'Rourke has probably wasted time campaigning in every county in the state of Texas. However, O'Rourke may be correct in his theory that Texas is less a Red State than a Purple State with voter registration problems. If his rather quixotic attempt to campaign everywhere does not derail the effort (one is reminded of Frederick the Great's dictum, "He who defends everything, defends nothing."), an attempt to increase voter registration and participation among the young, urban communities and in predominately Mexican-American South and West Texas could both have positive results and be difficult to properly account for in polling (something like the Trump campaign's getting inactive voters to become active in 2016).
If that is true, the fact that Sen. Cruz has had difficulty gaining a tremendous lead in the polls may be worse than it is generally believed.
"Blue Texas" is not a possibility in the short term. But Texas may have always potentially have been "Purple Texas." That may have had an impact even this year, where Sen. Cruz's unexpectedly stiff fight in a state containing some of the largest (and most expensive) media markets in the US may have drawn money that might have gone to other Senate races.