The impeachment route

One of the few certainties about war is its unpredictability: You can never be sure what you’ll wind up with, and that’s if you win. Impeachment, especially of a president, is the political equivalent.

A few thoughts, then, as the U.S. House of Representatives takes its initial steps in what looks like a probable impeachment of President Donald Trump.

Uncertainty is a central consideration. It might not happen in the House; at this writing (Tuesday afternoon) there’s not a clear majority in...