http://www.cnn.com/2017/09/08/politics/charlie-dent-paul-ryan/index.html

Washington (CNN)Amid the wall-to-wall coverage of Hurricane Irma and President Donald Trump's stunning debt ceiling deal with Democrats, you almost certainly never heard these two names: Charlie Dent and Dave Reichert. And, chances are, if you are a semi-normal person who doesn't follow politics obsessively, you don't recognize either man's name.

But the retirement announcements of these two moderate Republican House members from competitive swing districts is, without question, the most important political development of the week -- with potentially long-lasting consequences on Washington.

Why? Because both men represent an increasing abandonment of the current GOP by politicians in the ideological middle -- or, as Dent put it in a statement released Thursday night announcing his retirement, the "governing wing" of the Republican Party.
(Note: Democrats don't have much of a "governing wing" left, either, after losses in 2010 and 2014.)

It's worth quoting from that Dent statement as some length. Here's the key part: "As a member of the governing wing of the Republican Party, I've worked to instill stability, certainty and predictability in Washington. I've fought to fulfill the basic functions of government, like keeping the lights on and preventing default.

Regrettably, that has not been easy given the disruptive outside influences that profit from increased polarization and ideological rigidity that leads to dysfunction, disorder and chaos." It's hard to imagine a Democrat writing a more frank indictment of the current state of the Republican Party than that.

What Dent is making clear -- without exactly saying it -- is that he no longer thought it was worth fighting against the forces of rigid orthodoxy that had overrun his party. That he didn't leave the GOP -- it left him.