I explained in an article today "Why I Just Quit the Republican Party." This blog documents who else has publicly taken the same decision.
Those who beat me to this step: Mary Matalin, Jay Nordlinger, Jennifer Rubin, Joe Scarborough, and George Will. Not a very long list.
David Frum might be expected publicly to quit the party, but has not. At the same time, he does not hold that we who left have made a mistake:
Not everybody needs to belong to a political party, of course. There's a credible case that writers and intellectuals, in particular, should not belong to one: American public discussion is too often deformed by rote repetition of party talking points from people who should be thinking for themselves.
(July 21, 2016)
Oct. 16, 2016 update: Journalist Josh Barro joined the Democratic party.
Nov. 13, 2016 update: Journalist Max Boot and former Sen. Gordon Humphrey.
July 6, 2017 update: Daniel Drezner left in November 2016.
Oct. 1, 2017 update: John Kasich, one of the final Republican candidates for president in 2016 and governor of Ohio, is hinting at leaving the Republican party: "If the party can't be fixed, ... then I'm not going to be able to support the party. Period. That's the end of it."
Dec. 9, 2017 update: Peter Wehner left.
Mar. 23, 2018 update: William Kristol, a severe Trump critic, explains why he chooses to remain a Republican:
one thing conservatism teaches is not to embrace new realities too quickly. Some of those new realities turn out to be transient; others prove harmful. Isn't conservatism in part about resisting so-called new realities when you sense they might be questionable, even as people lecture you that you've got to get with the times?
So for now at least I'm choosing not to get with the times or go with the times. I'm choosing not to leave the GOP. I'm choosing not to accept the Trumpification of the GOP as an irreversible fact. ...
It's not just nostalgia for the good old days of Reagan and Bush and McCain and Romney that leads one to balk at giving up the Republican party to the forces of nativism, vulgar populism, and authoritarianism. It's also the fact that it would be bad for the country if one of our two major parties went in this direction. ...
the Republican party, it seems to me, is very much worth fighting for. Despite the current climate, the fight is not hopeless, and the stakes are high.
Jun. 20, 2018 update: Political consultant Steve Schmidt left with a Twitter blast.
Sep. 9, 2018 update: Asked if he ever contemplates leaving the Republican Party, Sen. Ben Sasse replied, "I probably think about it every morning when I wake up."
Sep. 16, 2018 update: Leslie Wexner, a long-time, major Republican donor, quit.
July 4, 2019 update: U.S. Representative Justin Amish of Michigan left the Republican Party because "our politics is in a partisan death spiral."
Feb. 1, 2020 update: In contrast to his Mar. 23, 2018 statement (quoted above), Bill Kristol has seemingly left the GOP.
Not presumably forever; not perhaps for a day after Nov. 3, 2020; not on every issue or in every way until then. But for the time being one has to say: We are all Democrats now.
— Bill Kristol (@BillKristol) February 1, 2020
Feb. 2020 update: Former U.S. Representative Joe Walsh quit the Republican Party.
Dec. 14, 2020 update: U.S. Representative Paul Mitchell of Michigan left the Republican Party because so many of its leaders have not accepted Trump's electoral loss. He became an independent. He leaves office in three weeks.
Feb. 10, 2021 update: Judging by this story, I was almost five years ahead of the masses: "'There's Nothing Left': Why Thousands of Republicans Are Leaving the Party."
Feb. 22, 2021 update: Jennifer Rubin, one of the first to quit, now argues that "Sane Republicans need to leave the GOP." She concludes with "An anti-Trump Republican is fast becoming an oxymoron."