(CNN) At first glance, the new CNN poll is a bit of good news for Republicans looking to the coming 2018 midterms with trepidation.

On the generic ballot question -- if the election were held today, would you vote for a Democratic or Republican House candidate -- Democrats hold a 5-point edge among registered voters, down from an 18-point advantage in a CNN/SSRS poll conducted in December 2017.

Those gains on the generic ballot are due, primarily, to a double-digit jump between December and now in enthusiasm about the midterms among Republicans and Republican-leaning independents.

That leap can be directly traced to the passage of President Donald Trump's tax cut plan at the end of last year and seems to justify the belief among GOP strategists that passing the tax bill was absolutely necessary to energize their base and give them a chance to avoid broad-scale losses in 2018.

That semi-surge on the generic, coupled with Trump's modestly-improving approval rating (he's at 40% in the new CNN poll, up from 35% in December) might well relieve some of the dread that many party strategists have been feeling about the coming midterms.

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