The predictable response from Democrats will be that Mr. Ryan couldn’t square his principles with the reality of Mr. Trump’s presidency. That might score a quick rhetorical win, but it misses the bigger political picture. America is in the midst of a major political realignment that is redefining both the left and the right. Mr. Trump’s sudden ascendance to power is a symptom of the larger trend and also a catalyst for the intellectual and political reformation that is currently underway on the right, which has led to the announced departures of standard bearers of the ancien régime like Senator Jeff Flake, Senator Bob Corker and now Mr. Ryan.

The job for House Republicans will be to select a new leader who isn’t just more of the same. The last effective leader was Newt Gingrich. Since he stepped down in 1999, Republican leadership has been either corrupt or incompetent. Tom DeLay was indicted (although he was eventually acquitted); Dennis Hastert is a convicted felon. John Boehner was a do-nothing placeholder who now works for a marijuana company; and Eric Cantor so infuriated his own constituents that he was defeated by an underfunded economics professor who still holds the seat. What we need is a clean break with the time-markers and careerists who are content being the party of no.