Trump has never tried to expand his base, to bring independents on board his so called Trump Train. Remember Trump won independents 46-42 over Clinton and because of the independent vote, the election. Today, 54% of all independent view Trump negatively, that is up 13 points from the end of January 2017. The question is, will independents turnout to vote against Trump and the GOP in the midterms because of their growing dislike of Trump? I think enough will to give the Democrats control of the House and probably giving the Arizona senate seat to the Democrats.
What's amazing is that most Republicans, Trump supporters in particular don't realize how much Trump's grating, obnoxious, egotistical, uncouth persona grates on those who aren't pro-Trumpers. Even when they support most of the things Trump does or is trying to accomplish. It's not that independents like the Democratic Party anymore than the Republican one. They don't. Only 19% of independent view the Democrats in congress favorably, 21% view Republicans in congress favorable. Both congressional parties are in the pits when it comes to independents. Total dislike of both. Questions 91A and B.
https://d25d2506sfb94s.cloudfront.net/cumulus_uploads/document/zq33h2ipcl/econTabReport.pdf
Yet, a majority of independents will end up voting for the Democratic congressional candidates over the Republican ones. One simple reason, Donald Trump's persona. They view their vote as a vote against Trump, not a vote for the Democrats. I repeat, not a vote for the Democrats, their party or their agenda. But you can bet your bottom dollar, your ranch, that the democrats will take it as support for them when it isn't. If there was a viable third choice, an additional option, that third choice would win hands down. Such is the dislike of both major parties. They're hated. The worst part of that, neither major political cares whether they're hated or not. Both know they have a monopoly and there isn't any other choice.
How's this for a future prediction. This year, 2018 because of our disliked of Trump we give the Democrats control of congress. In 2020 because of disliked and anger towards the Democrats who will be in power in congress, we re-elect Trump in 2020. Much like what we did with Obama. We didn't like his policies in 2010, got angry at him and elected a Republican House. We got mad at the Republican House and re-elected Obama in 2012. History does repeat itself.
FYI, independents make up approximately 45% of the total electorate today. How goes a general election is now dependent on the independent vote. Independents have no say on whom is nominated, but they decide the general.