Cook Political Report's Amy Walter ran the numbers on the Democratic party's blue wave last week and found that Trump's support may be a mile-wide in districts that he claimed in 2016, but only an inch deep as Trump didn't get 50% of the vote in a lot of districts. These shallow districts are where the Democrats targeted their House wins, and they peeled the GOP apart like an orange.
Not long after the November 2017 elections, I had lunch with David Petts, a Democratic pollster and longtime veteran of congressional campaigns. He remarked that the Republican gubernatorial candidates in Virginia and New Jersey performed within one to four points of President Trump in every congressional district in the state. The good news for the Republicans was that they didn’t lose districts that Trump easily carried. The bad news, even a GOPer not named “Trump” did not perform any better in districts Trump narrowly won or narrowly lost in 2016.
Petts handed me a spreadsheet that arranged the GOP-held congressional districts by Trump 2016 vote and argued Democrats should target every single district in which Trump took 55 percent of the vote or less. The theory being that Trump’s vote in 2016 would be the high-water mark for GOP candidates in 2018. As important to note were the significant number of districts that Trump won, but where his margin of victory masked his anemic vote share. Take New Mexico’s 2nd district. Trump won that district by 11 points, yet took just 50 percent of the vote. It was Clinton who underperformed there.
I tacked that chart onto the wall near my computer and watched it closely throughout the year. And, as Trump replayed his 2016 “all-base-all the time” strategy as president, it became clear he wasn’t going to be any more popular in the places that he lost, nor any less popular in the places that he won big. As such, the vote Trump took in a district in 2016, remained an accurate barometer for GOP vote share in 2018 in those districts.
Petts’ theory proved to be prescient. Of the 47 districts where Trump took less than 51 percent of the vote, Democrats have (so far) won 32 of them. If we exclude Utah’s four districts (in which Trump’s vote share was depressed thanks to the presence of third-party candidate and Utah native Evan McMullin), Democrats will have won at least 74 percent of the districts held by Republicans where Trump was the weakest in 2016.
Moreover, thirteen of those 32 districts were ones that Trump carried in 2016. In other words, using the number of seats held by Republicans that Trump lost (25) was the wrong metric. Vote share was the more appropriate standard.
For all the talk that open seats are what doomed Republicans, well-prepared incumbents weren’t any more resilient to the wave than GOP challengers. Only seven (non-Utah) Republicans outperformed Trump in their districts by more than five points. Five of those Republicans were incumbents; two were in open seats. Of those seven, only two of these strong over performers won: Reps. Mario Diaz Balart (FL-25) and John Katko (NY-24).
In two races that are yet to be called, but where the Democrat is favored - ME-02 (Poliquin) and NJ-03 (MacArthur) — Trump took just 51.4%. And, even the three ‘surprise’ wins for Democrats — SC-01, OK-05 and NY-11 — were in districts that Trump won with less than 54 percent.
In fact, at this point, there’s not one district that Democrats won that Trump carried by more than 54 percent of the vote.
Democrats took aim at the widespread weakness of the GOP nationwide and they won. As as Trump only gets more unpopular as we head towards 2020, expect another tier of House Republican districts to become vulnerable in two years.