One reason why House Republicans won't stand up to Trump: He won easily in most of their districts
From the moment Donald Trump secured the 2016 presidential nomination, throughout his Access Hollywood sexual-assault tape scandal, and even right up until today, Republican elected officials have overwhelmingly given him their full backing. There’s one incredibly important reason for why so many House Republicans in particular continue to stand by him: He carried the vast majority of the districts they represent by a very wide margin.
This fact is a crucial piece of context for why House Republicans so steadfastly support Trump even when polls show his national approval rating in the low 40s and debacles like National Security Adviser Michael Flynn’s resignation unfold almost daily. Republican members of Congress are almost all far more concerned with primary challenges than general election defeats because Trump remains almost uniformly popular both with the Republican base and with the swing voters in their districts who would put them over the top against a Democratic opponent.
Daily Kos Elections has calculated the 2016 presidential election outcome in all 435 congressional districts, which we’ve illustrated in the map at the top of this post that renders each district the same size. It reveals which party won each seat at both the presidential and congressional level (see here for a larger image or a traditional map). House Republicans won 241 seats in 2016, and Trump won 218 of those, meaning an outright majority of the House consists of Republicans in Trump districts. And in most of those 218 seats, Trump won handily, as we’ll explain further below.
The chart below, known as a histogram, graphs every Republican-won House district according to its 2016 presidential election margin. Trump carried half of the Republican-won seats by almost a 20-point margin or greater—all those to the right of the line marked “Median District”—and he bested Clinton by at least 10 points in 179 Republican-held seats, or roughly three-fourths of the GOP caucus. So even if Trump’s approval rating is in the low 40s nationally, there’s a good bet it’s higher in these types of districts.