It is at this level of legislative races — low visibility elections that carry exceptionally high stakes — that Democrats face intimidating Republican majorities. For Democrats to see across-the-board gains on the scale that Republicans achieved in 2010 would require not just a wave, but a tidal wave.

It is difficult to overestimate the political importance of the Midwest. The region was not only crucial to Trump’s victory, it has been crucial to continuing conservative control of both branches of Congress.

Matt Grossmann, a political scientist at Michigan State, put it this way on Twitter:

Some interpreted 2016 as beginning of possible realignment of the Great Lakes Midwest, with the white working class leaving Democrats. But this year, Senate races in those states are not even competitive for Republicans.

On Wednesday, Nate Silver, the founder of the political website 538, tweeted:

By far the Democrats’ strongest region in Senate + Gov + House polling has been the Midwest, and I don’t think you’d really gather that from the tonality of the reporting, which tends to fixate on demographic change and therefore finds races in the South & the West a lot sexier.

According to both Democratic and Republican operatives, Republican difficulties in the region stem in part from the trend among many Obama 2012-to-Trump-2016 voters to switch back to the Democrats.

Nick Gourevitch, whose Democratic firm, Global Strategy Group, is polling in the Midwest, wrote in an email: “In general, we are seeing Obama-Trump districts returning to the fold as competitive seats.” He went on:

Our postelection research on Obama-Trump voters showed that many of them were conflicted voters who had mixed feelings about supporting the president and that not all of them were the die-hard Trump supporters some in the media like to report them to be.

Gourevitch’s assessment is shared by a Republican consultant active in the region who requested anonymity to avoid alienating clients.

His studies, and polling by others in the region, he wrote me by email, show

that a significant portion of the Trump vote was comprised of nose-holders — that is, voters who weren’t particularly fond of Trump, but liked Hillary a helluva lot less, so they voted for Trump.

“These voters have not transitioned into strong Trump supporters, but rather Trump doubters,” the Republican consultant continued.

They may like the policies he’s espousing, but are turned off by his style of leadership. To say they are returning to the Democratic fold would be an overstatement because all the Democrats stand for is their opposition to Trump nowadays. Rather, these are swing voters — they voted for Trump, they may either not vote in ’18 or may vote Democratic.

The Republican consultant was less pessimistic about Trump’s Midwestern prospects in 2020. The “Trump doubters,” he argues,

are open for either side in ’20. They are certainly still open for Trump, depending on who the Democrats put up. Trump’s numbers may not be positive, but two years from now he may look at lot better than the candidate that survives the “lurch to the left” Democratic presidential primaries.

Celinda Lake, a Democratic pollster, agreed that while “in 2018, Trump’s victories in the Midwest are not paying off,” Democrats should “be more wary of 2020. In the Midwest and nationally, Republicans and especially Trump are ahead on economy and trade. That‎ could have real impact in 2020.” More immediately, Lake cautioned, “We do need to watch men who seem to be moving toward Trump in this last week” — referring to the aftermath of the bitter fight over the Supreme Court nomination of Brett Kavanaugh.