By The Numbers: How The Midterms Locked In Deeper Political Polarization

House minority leader Nancy Pelosi, D-CA, departs after a press conference with Democratic Congressional Campaign Committee  Chairman Ben Ray Lujan at Democratic National Committee headquarters in Washington, DC on November 6, 2018. - Americans started voting Tuesday in critical midterm elections that mark the first major voter test of US President Donald Trump's controversial presidency, with control of Congress at stake. (Photo by MANDEL NGAN / AFP)        (Photo credit should read MANDEL NGAN/AFP/Getty Images)
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The 2018 elections looked a hell of a lot like the 2016 elections, moved just a bit further left, as a hyper-polarization of the American electorate not before seen in the modern era continues to deepen.

Historically Republican suburban districts rejected the president’s party in droves, making it clear 2016 was no fluke. But Democrats failed to make much of a comeback in most of the rural areas they’d done well in historically.


Especially in the House, it almost didn’t matter how good or flawed a candidate was. If President Trump had lost the district, the Democrat was almost certainly going to win. If the president had won it by more than five points, the Republican was a near-lock to win. That almost identically syncs up to the 2018 national House vote, which as of the latest count Democrats won by about six points (that’s likely to climb a bit more with California’s ballots continuing to roll in).

There are 42 House districts that Democrats flipped or are still too close to call as of noon on Friday. More than half of them (22) are districts that Trump lost to Hillary Clinton, and another quarter (10) are districts where Trump beat Hillary Clinton by less than five points. Fully 33 of those 42 seats are districts where Trump didn’t win 50 percent of the vote. Only five of those 42 districts went to Trump by a double-digit margin, and none of those were by more than 15.5 percentage points.

Democrats didn’t win a single new House seat in districts where Trump topped 55 percent of the vote in 2016.

There were 25 Republican-held districts heading into Tuesday where Clinton had beaten Trump. Just three of those seats have definitely stayed red at this point. Reps. David Valadao (R-CA), John Katko (R-NY) and Mike Fitzpatrick (R-PA) are the only ones who won their reelection fights, and two of those three barely hung on against flawed opponents. Five of the races that remain too close to call fall in this category as well.

The biggest swing in the map relative to 2016 came in the GOP districts Trump lost or barely won. There are 20 House districts Trump won by less than five points. Democrats held eight of them before Tuesday — and picked up 10 more, giving them 18 of those 20, a major surge. These seats will undoubtedly be at the heart of the fight for the House in 2020.

Conversely, in safer GOP territory Democrats made almost no gains, unlike their 2006 wave election that brought a ton of immediately vulnerable Blue Dog Democrats to Congress (there are many new Blue Dog members, but they’re from safer seats this time around).

Rep. Collin Peterson (D-MN) is the only incumbent Democrat returning to Congress who holds a district that Trump won by a double-digit margin, and Democrats’ three losses all came in seats Trump won by solid margins. It’s worth noting that Peterson won his race by only five points against a virtually unknown challenger and will likely be vulnerable in 2020 — if he doesn’t decide to retire.

There will be a tiny number of members from districts that should be in the other party’s hands when the new Congress starts in January. At most, there will be six Democrats in Congress from districts Trump won by double digits, and at most eight Republicans from districts that Trump lost.


This pattern of polarization played out in Senate races as well, but there its effect broke against Democrats because of a historically tough Senate map.

Only two of the five Senate Democrats in states Trump won by double digits survived, and both of them had close calls. Sens. Joe Manchin (D-WV) and Jon Tester (D-MT) hung on, but each won by about three points against flawed opponents. Sen. Sherrod Brown (D-OH) also won in a state Trump had carried by eight points, but with a smaller-than-expected 6-point margin of victory in spite of his talents as a candidate and his opponent’s flaws.

Senate Democrats won their reelections in Michigan, Pennsylvania and Wisconsin, three states Trump barely won, coasted in every other blue state, and defeated Sen. Dean Heller (R-NV), the only Republican from a state Trump lost. Sen. Bill Nelson’s (D-FL) race is going to a recount in a state Trump won by just 1 point, and Arizona, which Trump won by 4.5 points in 2016, is still counting ballots.


Democrats had a good if not great night in governor’s results, winning seven new governor’s mansions. And while governor’s races diverged a bit more from national trends — Republicans held onto their Northeastern states of Vermont, Massachusetts and Maryland, for instance — this trend continued even in races that have less to do with federal politics.

Six of Democrats’ seven pickups were in states Trump lost or barely won — Illinois, Maine, Nevada, New Mexico, Michigan, and Wisconsin — with Kansas as the only exception. Democrats fell a few points short in Iowa and Ohio, former swing states that broke hard for Trump in 2016, with Florida (Trump +1) and Georgia (Trump +5) yet to be determined but not looking great for Democrats.


This trend creates very little political incentive for most members of Congress to work across the aisle. The Senate lost moderates like Sens. Joe Donnelly (D-MO), Heidi Heitkamp (D-ND) and Claire McCaskill (D-MO), while the House lost its own moderates, like Reps. Carlos Curbelo (R-FL), Mike Coffman (R-CO) and Leonard Lance (R-NJ). The only ones who will have to worry much about what the other side thinks are the Trump-district Democrats and the few swing-state senators up in 2020.

Even scandal didn’t seem to have the impact it once did. Sen. Bob Menendez (D-NJ) won comfortably in blue New Jersey, while indicted Rep. Duncan D. Hunter (R-CA) held on, and indicted Rep. Chris Collins (R-NY) appears to have won in a close race as well.

The good news for Democrats is a fair amount of their new House seats are in districts that should stay with their party if the 2020 election doesn’t end up looking much different from 2016 — unlike their last House majority, which was built heavily on heavily conservative rural districts that Democrats had no business holding in the long run.

The bad news is holding their newly minted majority means protecting the 26 to 29 (depending on final race calls) Democrats that hold seats Trump won. The post-2020 census redistricting maps likely will get a bit better for House Democrats overall heading into 2022, remaking this calculation, but that’s still a ways off.

In the Senate Democrats are also going to need to figure out a way to break through in a number of states Trump won in 2016 to win back the upper chamber anytime soon.

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