The first thing to keep in mind is that turnout invariably drops between a presidential election and the next midterms. So 2018 is mainly a battle over two questions: Which party will do a better job of mobilizing its 2016 voter base? And what will happen in swing districts?
On a net basis, the Kavanaugh affair could bring out hardcore Trump voters outraged that the judge is being accused of a sexual episode dating back to high school. Or it could bring out women and liberals even more strongly. Trump’s vilification of Dr. Blasey Ford didn’t help his cause.
In addition, it’s impossible to believe that that whole spectacle will be good for Republicans in swing districts. The classic swing voter is a suburban Republican woman, already somewhat disaffected from Trump and very likely grossed out by Kavanaugh and the Republicans’ shabby treatment of Blasey Ford.
The Republicans have been crowing that the lead for the generic Democrat in House races has fallen slightly, but that depends on what you are comparing. According to Nate Silver of 538.com, the Democrats’ chances of taking the House are exactly where they were a month ago, the day before the initial Kavanaugh confirmation hearings began—with odds of nearly three-in-four.
And every time the nonpartisan Cook Report updates its projections, more Democrats are favored to take Republican-held seats. Cook now rates 14 competitive seats as likely Democrat and another 29 Republican held seats as toss-ups. If Democrats win just half of those, they take the House majority.
Which way Kavanaugh cuts in November will tell us something about ourselves as Americans.