Congressional Republicans are not a group Trump can easily afford to lose. They have a lot of power to check Trump’s presidency, from modest measures such as treating his Cabinet nominations with more scrutiny to extreme ones like supporting his impeachment and removal from office. Obviously that’s getting way, way ahead of ourselves, and Trump’s approval ratings remain very strong among Republicans for now. That may constrain how much members of Congress push back against the president. But the conventional wisdom is arguably too dismissive of the possibility of an inflection point. Richard Nixon’s approval ratings had been in the low-to-mid-80s among Republican voters for years, but they suddenly fell into the 50s over the course of a few months in 1973. He resigned in August 1974.
But if Trump wants to get re-elected, his biggest problem isn’t what Republicans think about him; it’s what the rest of the country does.
The lesson of the midterms, in my view, was fairly clear: Trump’s base isn’t enough. The 2018 midterms weren’t unique in the scale of Republican losses: losing 40 or 41 House seats is bad, but the president’s party usually does poorly at the midterms. Rather, it’s that these losses came on exceptionally high turnout of about 119 million voters, which is considerably closer to 2016’s presidential year turnout (139 million) than to the previous midterm in 2014 (83 million). Republicans did turn out in huge numbers for the midterms, but the Democratic base — which is larger than the Republican one — turned out also, and independent voters strongly backed Democratic candidates for the House.