When that gavel’s so close you can almost grasp it. Photo: Jonathan Wiggs/Boston Globe via Getty Images

The past couple of weeks of polling have triggered many a liberal’s Post-Trump Stress Disorder. For most of last year, Democrats enjoyed a nearly double-digit lead in the generic 2018 congressional ballot, while Donald Trump’s approval rating sat beneath 40 percent — and the GOP’s top agenda item looked to be the most unpopular piece of tax legislation in modern American history.

Thus, as progressives watched Scott Pruitt turn the EPA into a division of the American Petroleum Institute, Mick Mulvaney rebrand the CFPB as the Payday Lenders Protection Racket, and the Koch Brothers capitalize on their big investment in oligarchy futures, they could take heart in the thought that the bad guys weren’t going to get away with it — Paul Ryan would lose his gavel in 2019. By late December, FiveThirtyEight’s poll of polls had the public favoring a Democratic Congress over a Republican one by 13 points; the question wasn’t whether Team Blue would win a historic victory in this year’s midterms, but rather how historic that triumph would be.

A little over a month later, the Democrats’ polling advantage has narrowed to just six points — a margin that would likely be too small for the party to overcome Republican gerrymandering to reclaim the House. Meanwhile, Trump’s approval rating has cracked 40 percent for the first time since last May, and the GOP tax bill, while still not popular, is steadily gaining support. Some pundits started to rethink their predictions of a blue wave; some progressives started to reread the FAQs for immigrating to Canada.

But such pessimistic panic was more than a little premature — as voters in Missouri demonstrated last night.

The case for bullishness about the Democrats’ prospects never rested on polling alone. Since Trump took office, the party has consistently wildly overperformed in special elections. And that trend continued last night, when 27-year-old Democrat Mike Revis won election to the Missouri statehouse, in a district that had backed Trump over Hillary Clinton by 28 points in 2016. With Revis’s victory, Democrats have now taken 35 state legislative seats away from Republicans since the Trump era began.

Team Blue did lose the three other special elections in the Show-Me State last night. But in all of those races, the party’s candidates improved on Clinton’s showing by extraordinary margins — including a whopping 53-point gain in House District 144.

There were 4 specials in MO today, all in very red districts. Here are the net swings compared to the 2016 presidential results:#HD97: +31% net swing towards Dem [& Dem pick-up]#HD39: +19%#HD129: +25%#HD144: +53% (!)



(This is the state ft. McCaskill's reelection race) — Taniel (@Taniel) February 7, 2018

Needless to say, the GOP’s House majority could not survive a 19-point swing this November, let alone a 53-point one. And last night’s results are especially encouraging for Democrats because of where they occurred. Missouri senator Claire McCaskill might be the party’s most vulnerable incumbent in the upper chamber. To keep her seat this fall, McCaskill will need extraordinary Democratic turnout. She now has reason to expect the extraordinary.

Furthermore, there’s been some anxiety in Democratic circles that the backlash to Trump might prove to be concentrated on the coasts (perhaps the Virginia suburbs are turning blue, but the Midwest is still growing red as rust). But that worry looks increasingly unfounded. Last month, Democrats won a seat in Wisconsin’s State Senate, a seat that had been held by Republicans since 2001. The result was so unnerving for the Badger State GOP that Governor Scott Walker is now refusing to hold any more special elections this year, in arguable defiance of state law. Last night’s strong showing in Missouri confirms that #TheResistance has traction in America’s heartland.

In our era of hyperpolarization, all elections are won on turnout. But this is especially true of midterm contests — and while the generic ballot is narrowing, the enthusiasm gap is still looking cavernous.