The substance of Trump's 2020 campaign

Donald Trump is the first president in American history to run for re-election after having been impeached. We should expect his second presidential campaign to be as singular as everything else in his still-astonishing political career has been.

There is another sense, however, in which his second campaign looks very familiar. Externally speaking, Trump is an ordinary incumbent president who should enjoy all the benefits traditionally associated with such a position. Despite the warnings of economists earlier this year, there has been no recession. His approval rating is about even...