Donald Trump's Outrageous 2020 Advantage

In the 2020 presidential race, President Trump has several legs up. The most obvious is incumbency. Most of the American presidents who sought re-election since 1900 — including all but George H.W. Bush in the last 35 years — won a second term. Those are good odds, which become even better if Trump avoids a recession between now and Election Day.

Then there’s the Electoral College. Despite the president’s repeated claims that it favors Democrats, the results in 2016, when Hillary Clinton won nearly three million more votes than he...