Democrats, with the Affordable Care Act, found how difficult it can be to change initial impressions of a big policy change enacted along partisan lines. (And that measure was judged more favorably from the start than the Republican tax bill.) The ACA proved an anchor around the necks of Democrats in the 2010 election, which ended up as one of worst drubbings for a party in power in generations.

“That’s a good demonstration that it’s difficult to take a bill that’s underwater and change public perceptions,” said Bill McInturff, a Republican pollster and part of the bipartisan duo that conducts the NBC-Wall Street Journal surveys. “We have to acknowledge that.”

But McInturff said the tax measure could be a chip on the table for Republicans in the midterm sweepstakes. If 2018 is an even stronger year economically, he said, there is an opportunity for Republicans to connect that performance to the tax bill and claim credit.