To hear Democrats tell it, the Republicans may as well fold up their tents and concede control of the House now.  The conventional wisdom states that Trump is so hated that Democrats will turn out in droves to unseat GOP incumbents and hand the Democrats a big win.

There's only one problem with "conventional wisdom" – it's usually wrong.  In this case, a new poll out from NBC News-Wall Street Journal shows Republicans actually narrowing the gap on the generic House ballot. 

Previously, Democrats held a comfortable double-digit lead.  But the latest numbers show the GOP closing that gap to just 7 points.

NBCNews:

But the poll doesn't show "knockout numbers" for Democrats, which gives Republicans a chance of retaining control of Congress, says Republican pollster Bill McInturff of Public Opinion Strategies, who conducted this survey with Democratic pollster Peter Hart and his team at Hart Research Associates.

"You don't see knockout numbers here in April.  You see problematic numbers [for Republicans]," he said.

In the poll, Democrats enjoy a 7-point advantage in congressional preference, with 47 percent of voters wanting a Democratic-controlled Congress, and with 40 percent preferring a GOP-controlled Congress.

That's down from the Democrats' 10-point edge in March, 50 percent to 40 percent, although the change is well within the poll's margin of error.

In past wave cycles for Democrats – in 2006 and 2008 – the NBC/WSJ poll typically found Democrats with a solid double-digit lead in congressional preference.

But turnout may be a big problem for the GOP.  The so-called "enthusiasm gap" between the two parties is significant.

But the current poll shows Democrats with a significant advantage in enthusiasm, with 66 percent of Democrats expressing a high level of interest (either a "9" or "10" on a 10-point scale) in November's elections, versus 49 percent for Republicans.

That's a reversal from the merged NBC/WSJ polling data in 2010 – a wave year for Republicans – when 66 percent of Republicans expressed a high level of interest, compared with 49 percent for Democrats.

And among these high-interest voters in this new poll, Democrats lead Republicans in congressional preference by 21 points, 57 percent to 36 percent.

"That enthusiasm is a very powerful signal of a Democratic edge," McInturff said, but he cautioned that high-interest voters "are a fraction of all overall voters."  (Not every voter is a "9" or "10.")

One thing the "enthusiasm gap" doesn't show is how many of those voters will actually turn out on election day.  That could be the GOP's saving grace.

Historically, Democratic core constituencies like the young, minorities, and single women simply don't vote.  Democrats point to the fanatical anti-Trump hatred among their base as "proof" that history will change this time.  There is also the prospect of a Democratic victory that may drive their voters to the polls.

Until it happens, Republicans need a maximum effort to get their own voters to the polls in order to stave off disaster.  The Democrats' former advantage in online organizing is gone, with Republicans being at least as good as Democrats at identifying their voters and targeting messages designed to move them to vote in November.

At this point, it appears that the race for control of the House is going to be a lot closer than Democrats are willing to admit.