To win in November, Republicans need to take a page from Obama’s playbook

If history is any guide, Republicans could be in store for a beating at the ballot box in November.

President Donald Trump’s average approval rating has dipped below 40%, while his disapproval rating has climbed into the high 50s. In previous elections, when presidents had approval ratings below 50%, their parties have almost always performed poorly in the midterms. Trump is nowhere near that threshold.

Congressional Republicans are not doing much better. The generic ballot shows that most midterm voters favor Democrats...