For all the spinning and posturing there remains a fundamental challenge for the Republicans: the tax bill won’t become more popular unless the president becomes more popular. In fact, if you look at national support for the tax legislation, you will see that it lines up almost exactly with voters’ overall perception of the president. In other words, if you like the president, you like the tax reform legislation. If you don’t like Trump, you either don’t like the bill or you are undecided about it. It is a reminder that whatever the president touches carries his polarizing brand. Even as voters are overwhelmingly positive about the economy, it doesn’t translate to their opinions of the president or the tax law. The chart and the quote above are from the Cook Political Report. It seems that the Republicans new tax law is as unpopular as their president. That's not good for them. They were counting on that tax law to save them in the coming election.
That means their prospects in the coming election are still tied to Donald Trump -- and Trump is the most unpopular president since World War II. Can he change that perception? I doubt it. The people don't like his agenda, and they don't trust him (don't think he is honest).