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By Scott Lemieux

Midterm elections are all about the turnout. Not only do smaller numbers of voters generally participate in midterm elections, midterm electorates tend to skew whiter, older and more affluent — and hence more Republican — than presidential ones. The 2018 midterms may, however, be an exception, with Democratic voters potentially more mobilized than Republicans.

For instance, in what will be a fascinating race to watch, Tallahassee Mayor Andrew Gillum, who is African-American, scored an upset win in the Democratic gubernatorial primary over former Rep. Gwen Graham. Gillum will face the very Trumpian Rep. Ron DeSantis — who has already encouraged Floridians not to “monkey this up” by voting for Gillum — in a direct challenge to a diverse Democratic coalition. As with Stacey Abrams’s gubernatorial race in Georgia, Democrats are hoping that historic African-American candidacies can mobilize turnout from minorities threatened by the Trump administration, as happened in the Alabama Senate race last year.

Still, Democrats winning back the House of Representatives is far from guaranteed, which, given how the poll numbers look right now, represents a major potential failure of American democracy.

The stakes of the 2018 elections would be hard to overstate. Republicans are openly acknowledging the Democrats winning the House would mean potentially explosive investigations into Trump administration scandals that House Republicans have actively covered up. The next two years of American politics will play out very differently if House committees are controlled by Democrats performing actual oversight or men like House Intelligence Committee Chair Devin Nunes, R-Calif., remain in control and continue on a worldwide series of wild goose chases in a desperate attempt to prop up Trump.

Republicans, at least to some extent, are reacting by denying that they can lose at all. One recent survey indicated that only 28 percent of Republicans believe that their party would lose control of the House in 2018. This is not necessarily great news for the party, even though it might reflect that voters that are happy with the party, it suggests that their voters that are complacent while Democrats are determined to take over the House.

Meanwhile, the not-fake news cautious optimism on the part of Democrats: Democrats have a 7-point advantage in polls that ask about general partisan preferences rather than specific candidates or races. The results of actual elections also suggest that a strong Democratic performance is coming: Even the recent Democratic loss in Ohio’s 12th District is bad news for Republicans, given that the GOP barely held on to a strongly pro-Republican district.

Another aspect of Tuesday’s primaries that might have ramifications for the midterms is the power of the teacher’s movement in states that have chronically underfunded education. Six Republican legislators in Oklahoma lost their primaries and another dozen were forced into runoff elections after failing to secure a majority, primarily because of their opposition to a tax increase that would provide more funding to pay teachers and other government employees. This is the latest example of a trend that has accelerated throughout 2018, catalyzed by the strikes by educators in multiple states.

Oklahoma itself is not about to go blue, of course, but the revolt against Republican state legislators starving essential public services might have tarnished the Republican brand enough to present to pickup opportunities in red states.

And it’s not just deep red states where labor interests appear to be well-mobilized. In the critical swing state of Wisconsin, Democrats have had success in multiple special elections since 2016. Wisconsin’s fiercely anti-labor governor, Scott Walker, is in serious trouble, and defeating Walker would be a major victory for beleaguered labor organizations and their progressive allies.

And yet, despite all this good news for Democrats, the outcome of the midterm elections remains very much an open question. The site 538.com estimates that Democrats have a 75 percent chance of taking the House — good odds, but frighteningly similar to the odds of Hillary Clinton winning on election night. And the Senate map is so strongly tilted against Democrats that even a very strong performance may not be enough for Democrats to take the Senate and end Mitch McConnell’s ability to pack the federal judiciary with hard-right Republicans.

The problem for Democrats is that a combination of districting that favors rural conservatives, aggressive partisan gerrymandering by Republican statehouses, and Republican vote suppression means that Democrats have to win by a large margin to get even narrow control of the House. Republican complacency might ultimately be justified — for the worst possible reason.

CORRECTION (Aug. 30, 2018, 9:51a.m.): An earlier version of this article incorrectly identified the Florida city of which Andrew Gillum is the mayor. It's Tallahassee, not Jacksonville.

Scott Lemieux is a lecturer in the Department of Political Science at the University of Washington. He is the co-author of Judicial Review and Democratic Theory and contributes regularly to The Week, Reuters, and the New Republic.