I think this data suggests that Trump won’t become significantly more popular simply by emphasizing “peace” (his North Korea diplomacy) and “prosperity” (the economy) — a message that Republicans have started to push. Trump’s popularity — and thus the GOP’s midterm fortunes — is likely being dragged down by his personality characteristics and behavior. He should probably, say, stop tweeting. He would likely help his position if he stopped telling so many lies.

Trump’s more unusual policy moves also seem to be costing him support. His conservative stances on immigration may be how he won the Republican primary in 2016, but I doubt that policies like separating children from their parents at the border are helping with how Americans view his immigration agenda. And feuding with Canadian, Mexican and European leaders over tariffs is unlikely to help his standing on foreign policy.

It’s worth considering: If Trump is at 40 percent approval right now, despite the strong economy, would a more typical Republican president be in the upper 40s or even at 50 percent?