Every big U.S. election is interesting, but the coming midterms are fascinating for a reason most commentators forget to mention: The Democrats have no issues. The economy is booming and America’s international position is strong. In foreign affairs, the U.S. has remembered in the nick of time what Machiavelli advised princes five centuries ago: Don’t seek to be loved, seek to be feared.

The contrast with the Obama years must be painful for any honest leftist. For future generations, the Kavanaugh fight will stand as a marker...