This is the kind of thing that makes me feel like neither party really knows what it's doing. If you're going to create some big tax bill, passing it early on in your presidency is the worst possible choice you can make. Now, the American people can judge the outcome of that bill and will vote accordingly in 2020. If they'd simply waited to pass that bill until just before the midterms in 2018 and had it take effect in 2020, then no one would truthfully be able to say that the bill had failed. This isn't even some deep insight I'm making here - it should have been brought up within the first five minutes of the first meeting of creating the bill.

You could argue that the strategy may have been to stanch their losses in the 2018 election....but that election went almost as badly as it could possibly have gone for the right anyway (depending on who you ask).