UPDATE (5/3): The following piece has been updated with additional examples of conservative pundits who say they will not support the likely Republican nominee in November. 

Right-Wing Pundits Vow To Stay Home, Vote Third Party, Or Vote For Clinton

Mark Levin: “I Am Not Voting For Donald Trump. Period.” The conservative radio host reacted to an attack on him by Trump ally Roger Stone by declaring, “I am not voting for Donald Trump. Period.” He added, “Count me as never Trump.” [Breitbart.com, 4/8/16]

Radio Host Charlie Sykes: “When I Say Never Trump, I Mean Never Trump.” Skyes, a Wisconsin-based conservative commentator, has repeatedly promoted the Never Trump movement. He conducted a critical interview with Trump, during which he heavily criticized the Republican candidate. [NPR.org, 4/1/16; The New York Times, 4/4/16; Twitter.com, 5/3/16]

George Will: Republicans Must Keep Trump Out Of The White House. Will wrote an April Washington Post column headlined, “If Trump is nominated, the GOP must keep him out of the White House.” Will concluded: “If Trump is nominated, Republicans working to purge him and his manner from public life will reap the considerable satisfaction of preserving the identity of their 162-year-old party while working to see that they forgo only four years of the enjoyment of executive power.” [Washington Post, 4/29/16]

Law Blogger David Bernstein: “I’d Rather Hillary Clinton Win.” Bernstein, a Volokh Conspiracy blogger and law professor, wrote that Trump is “a crude charlatan, an ignoramus, a fraud, conducting a modern medicine show that combines the worst of politics with the worst of professional wrestling.” He added “I’d rather Hillary Clinton win. I’d rather (and I never thought I’d say this) Barack Obama serve a third term. I’d even rather Bernie Sanders win, though if it came down to Sanders vs. Trump it might be time to form a breakaway republic. If Trump wins the nomination, I will actively seek to prevent him from becoming president.” [WashingtonPost.com, 5/2/16]               

Radio Host Michael Berry On Supporting Trump: “I Don't Vote For Democrats.” Berry, a Texas-based radio host and Cruz supporter, has repeatedly said he would not support Trump in the general. Berry responded to a question about supporting Trump in November by tweeting: “No, I won't. I don't vote for Democrats. #NeverTrump.” He also wrote: “You vote for @realDonaldTrump. I will not. You can have your con man tyrant. You can buy his snake oil. I never will. Ever. #NeverTrump.” [Media Matters, 3/1/16; Twitter.com, 3/10/16, 5/2/16, accessed 5/3/16]

Fox’s Guy Benson: I Won’t Vote For Trump Or Clinton. Benson, a Fox News contributor and Townhall.com editor, tweeted of the prospect of voting for Clinton and Trump: “I certainly won't, nor will I vote for him. Both are unfit statists.” [Twitter.com, 4/29/16]

Max Boot, Niall Ferguson, And Frances Townsend Pledged To Not Support A GOP Ticket With Trump. Conservative commentators Boot, Ferguson, and Townsend signed an open letter stating that “as committed and loyal Republicans, we are unable to support a Party ticket with Mr. Trump at its head.” [WarOnTheRocks.com, 3/2/16]

Writer Mark Salter: If The GOP Nominates Trump, “I'm With Her.” Salter, a Republican adviser and speechwriter who has frequently collaborated with Arizona Republican Sen. John McCain, tweeted: “the GOP is going to nominate for President a guy who reads the National Enquirer and thinks it's on the level. I'm with her.” He wrote in January that “Nothing anyone could reveal about Trump could get me to change my opinion that he's an asshole.” [Twitter.com, 5/3/16; Esquire, 1/12/16] 

Glenn Beck: “I Won't Vote For Hillary Clinton, And I Won't Vote For Donald Trump.” Beck, who endorsed Sen. Ted Cruz (R-TX), pledged during a December 2015 Fox News interview that he would not go to the polls in November if Trump wins the nomination:

GLENN BECK: I know that I won't go to the polls. I won't vote for Hillary Clinton and I won't vote for Donald Trump. I just won't. And I know a lot of people that feel that way. I know people in the GOP who are like, look, well he is better that Hillary Clinton. Maybe, I don't know. I mean the guy last night, he didn't even know what the triad was. He didn't even know what are the missile silos and the strategic air command with missiles on the planes and our nuclear submarines. He didn't even know what that meant. He couldn't answer that question. It was bizarre. He is also a giant progressive. So I can't vote for progressive. I can't vote for Hillary, and I can't vote for him. I said, probably a year and half ago that I thought we were entering the times of the Whig Party. That the Republicans were going to go to the way of the Whigs, who they demolished back in Abraham Lincoln's time. I think that's happening. They have not, they got power, they said we just have to have a House and Senate. We got it. Now they say, we have to have the House and the Senate and the White House. Well wait a minute, we heard that before with George W. Bush. They're not listening. They're not doing what the people have hired them to do. If they put Donald Trump in, try to put him in office, if that's what the people want, you are going to see an end to the Republican Party. It will just be over, there'll just be nothing left. [Fox News, The Kelly File, 12/16/15, via Media Matters] 

Fox's Erick Erickson: “I Will Not Vote For Donald Trump For President Of The United States Even If He Is The Republican Nominee.” Erickson, a Fox News contributor and radio host, has repeatedly said he would not vote for Trump in the general election. From a post on his website The Resurgent:

I will not vote for Donald Trump for President of the United States even if he is the Republican nominee.

He is an authoritarian blending nationalist and tribal impulses, which historically has never worked out well for the nation that goes in that direction or the people in that nation.

He will not win in November. He will not win because he turns off a large number of Republicans; he turns off women; he turns off hispanic voters; he turns off black voters; and the blue collar voters who support him are not a sufficient base of support to carry him over the finish line. His supporters who claim he carried hispanic voters in Nevada are deluding themselves. Nevada's turnout of hispanic voters was less than one percent of Nevada's hispanic population, amounting to around 100 people in the exit polling with a margin of error of at minimum ±10%.

Trump is a liberal who has supported big government, interventionist policies. He defends Planned Parenthood, says he can cut deals in Washington, and believes in a socialist government run healthcare scheme. [The Resurgent, 2/27/16]

Erickson has said he would not vote for Clinton but suggested he would like a third party candidate and encouraged former Texas Gov. Rick Perry to run under a third party banner. [CNN.com, 2/29/16; The Resurgent, 2/24/16]

Weekly Standard's Bill Kristol: “I Would Try To Recruit A Real Conservative To Run.” The New Yorker's Ryan Lizza reported that “Trump represents such a radical break with the Republican consensus on important issues that a significant segment of the Party will never back him.” He interviewed Kristol about Trump:

The strongest resistance to Trump comes from the foreign-policy establishment of the Republican Party. Bill Kristol, the editor of The Weekly Standard, which is best known for its advocacy of a hyper-interventionist foreign policy, told me that there was no chance he would ever back Trump. “I've been Sherman-esque--and more!,” he said in an e-mail, “since I've said I would try to recruit a real conservative to run as a fourth (Bloomberg being the 3rd) party candidate.” He added (without irony, I think) that “Dick Cheney-Tom Cotton would be the ideal ticket, but am working on others that approach that high level.” [The New Yorker, 2/26/16]

Kristol also told The Daily Caller: “Couldn't vote for Trump, couldn't vote for Hillary.” [The Daily Caller, 12/1/15]

CNN's Kevin Madden: “I'm Prepared To Write Somebody In So That I Have A Clear Conscience.” The Washington Post quoted Madden, a former Romney adviser who works as a CNN commentator, stating of Trump:

“For many Republicans, Trump is more than just a political choice,” said Kevin Madden, a veteran operative who advised 2012 nominee Mitt Romney. “It's a litmus test for character.”

Madden, like some of his peers, said he could never vote for Trump. If he is the nominee, Madden said, “I'm prepared to write somebody in so that I have a clear conscience.” [The Washington Post, 2/28/16]

New York Times' Peter Wehner: “I Will Not Vote For Donald Trump If He Wins The Republican Nomination.” Wehner, a Times contributing opinion writer who served in three Republican administrations, pledged to not support Trump or Clinton in November:

Beginning with Ronald Reagan, I have voted Republican in every presidential election since I first became eligible to vote in 1980. I worked in the Reagan and George H. W. Bush administrations and in the White House for George W. Bush as a speechwriter and adviser. I have also worked for Republican presidential campaigns, although not this time around.

Despite this history, and in important ways because of it, I will not vote for Donald Trump if he wins the Republican nomination.

I should add that neither could I vote in good conscience for Hillary Clinton or any of the other Democrats running for president, since they oppose many of the things I have stood for in my career as a conservative -- and, in the case of Mrs. Clinton, because I consider her an ethical wreck. If Mr. Trump and Mrs. Clinton were the Republican and Democratic nominees, I would prefer to vote for a responsible third-party alternative; absent that option, I would simply not cast a ballot for president. A lot of Republicans, I suspect, would do the same. [The New York Times, 1/14/16] 

Washington Post's Robert Kagan: “The Only Choice Will Be To Vote For Hillary Clinton.” Kagan, a Reagan administration official and Iraq War cheerleader, wrote in a Post column: “The Republicans' creation will soon be let loose on the land, leaving to others the job the party failed to carry out. For this former Republican, and perhaps for others, the only choice will be to vote for Hillary Clinton. The party cannot be saved, but the country still can be.” [The Washington Post, 2/25/16]

Washington Examiner's Philip Klein: “11 Reasons This Conservative Would Never, Ever, Ever Vote For Trump.” Klein, the Washington Examiner's managing editor, offered 11 reasons he wouldn't support Trump in the general election, including,  “He's a megalomaniac who doesn't understand constitutional limits on executive power.” And, “I don't want Republicanism that's served with an entree of racism and sexism.” [Washington Examiner, 2/24/16]

Iowa Radio Host Steve Deace: “I Will Not Lend My Name And An Ounce Of Integrity To This Reality Television Star's Charade.” Deace, a Cruz campaign surrogate, cited a litany of reasons he wouldn't support Trump in the general election, including Trump's refusal to disavow racists. Deace also labeled Trump “an unrepentant serial liar and adulterer.” He wrote of his November vote:

Conservativism is supposed to be about conserving the things that created American Exceptionalism--not defining them down to play a part in a cult of personality. Neither is it supposed to be about race-baiting, ethnic tribalism, authoritarianism, support for Planned Parenthood or progressivism. That's the left, but that's also Trump, who's just repackaging our opponent's views in pro-American terms.

Therefore, should Trump be the nominee I will not lend my name and an ounce of integrity to this reality television star's charade. Now, should you feel compelled to vote for him because he's not Hillary, I want you to know I won't condemn you, either, provided you're not being intellectually dishonest in the process. [Conservative Review, 2/29/16]

The Federalist's Tom Nichols: “I'll Take Hillary Clinton Over Donald Trump.” Nichols, a professor at the U.S. Naval War College and at the Harvard Extension School, wrote on the conservative website The Federalist: “If forced into a choice between Clinton and Trump, I will prefer Hillary Clinton. The future of the entire conservative movement is at stake, and a Clinton victory over Trump might be the only hope of saving it.” He added: “In the end, a Trump administration will not only avert the first chance at unified Republican government in years, but will finish off the conservative movement itself.” [The Federalist, 2/24/16]

The Federalist's Bethany S. Mandel Would Prefer “Even Hillary Clinton To Trump.” The Daily Beast reported that Mandel would support Clinton over Trump:

Conservative essayist Bethany S. Mandel, who has been awash in a deluge of social media abuse since she began denouncing Donald Trump, finally purchased a handgun over the weekend.

[...]

Yet one can hardly fault Mandel's feelings of vulnerability. Typical online insults (screenshots of which she provided to The Daily Beast) included “you deserve the oven,” complete with the image of a Domino's Pizza oven--this from an apparent Trump fan who goes by the Twitter handle @dinguscout.

After Mandel observed: “Another night blocking all the anti-Semites who are helping Trump make American[sic] great again,” a second apparent Trump supporter, @unusr1, tweeted at her: “Missed one, you slimy Jewess.”

[...]

Thus Mandel--who prefers Texas Sen. Ted Cruz, Florida Sen. Marco Rubio or, as a desperate last resort, even Hillary Clinton to Trump--recently engaged in an online skirmish with Breitbart's Washington political editor, Matthew Boyle. [The Daily Beast, 3/1/16]

Conservative Writer Doug Heye Won't Support Trump “Because Of Trump's Perversion Of Conservatism, Along With The Devastating Impact He Would Have.” Heye, a former communications director for the Republican National Committee who frequently writes on politics, explained why he “cannot support Donald Trump were he to win the Republican nomination” (emphasis in original):

Because of Trump's perversion of conservatism, along with the devastating impact he would have if nominated, I cannot support Donald Trump were he to win the Republican nomination.

As the GOP battles over what - or who - defines conservatism, it should be easy to define what doesn't: angry populism, cheap sloganeering and bombast.

[...]

As a loyal and proud conservative Republican, I cannot help make that happen by voting for a Trump-led ticket in 2016. [Independent Journal Review, January 2016] 

Ricochet's Claire Berlinski: “I'd Vote for Hillary Before Trump.” Berlinski, a conservative writer and a Manhattan Institute scholar, wrote a post explaining “Why I'd Vote for Hillary Before Trump.” She cited Trump's views on the Bush administration's handling of Iraq (emphasis in original):

The moment that most clearly demonstrates that he's nuts -- and nuts in a way different in kind from any previous president in the nuclear era and from any of the other candidates for the presidency -- was when he said George W. Bush knowingly misled the world about Iraq's weapons of mass destruction. “I will tell you. They lied. And they said there were weapons of mass destruction and there were none. And they knew there were none. There were no weapons of mass destruction.”

[...]

I have many other objections to him, but I think this one is -- as George Tenet might say -- a slam dunk.* You can't put people who believe things like that in the White House. It's too dangerous. [Ricochet, 2/25/16] 

Washington Examiner's David Freddoso: “I've Made Clear I'll Be Looking For A Third Party Candidate.” Freddoso, an Examiner contributing editor, has repeatedly tweeted the anti-Trump hashtag #NeverTrump, writing that “I've made clear I'll be looking for a third party candidate,” and “I wouldn't ever support someone like him and he'll lose anyway so why defile myself by considering him.” [Twitter.com, 2/27/16, 2/27/16]

CNN's Tara Setmayer: “I Will Never Vote For Him. EVER.” Setmayer, a CNN political commentator who worked for Rep. Dana Rohrabacher (R-CA), has tweeted that she is “not deceived by Trump's manipulation. I will never vote for him. EVER. I'm a real conservative.” She's also made clear she will not vote for Trump even if he's the Republican nominee. [Twitter.com, 2/29/16, 3/1/16]

GOP Strategist And Writer Rick Wilson: “With God As My Witness, I Will Never Vote For Donald Trump.” Wilson, a Republican consultant and conservative writer, wrote: “I will never vote for Donald Trump, not even if Ronald Reagan and William F. Buckley rise from the grave and beg me to support him” and concluded:

I have opposed Trump from the first day of his wretched, crapulous campaign. I have opposed Trump when his clownish minions called my clients seeking to have me fired. I have opposed The Donald when his slavish of Trumpbart stooges ran story after story attacking me, and unleashed their fever-swamp yokels on my email, my phone, and my family.

I will continue to oppose Trump, implacably and unceasingly.

I will not bend. I will not cease this fight. I will never embrace this thuggish, venal, gibbering psychotic, and I will not countenance those who do. I don't care if I'm the last Republican in America standing to resist this man, but with almighty God as my witness, I will not vote for Donald Trump. [Independent Journal Review, February 2016]

GOP Strategist And Writer Liz Mair: “I Will Either Vote Third Party Or Do A Write-In, Potentially Of Myself.” Mair, a Republican strategist and blogger, told The New Yorker in an email: “I have repeatedly stated that if he is the GOP nominee, I will either vote third party or do a write-in, potentially of myself. At least if I do the latter thing, I know I'm voting for someone I 100% agree with for once :).” [The New Yorker, 2/26/16]

Conservative Writer Eliot A. Cohen Would Vote For Clinton Over Trump. Cohen, a Johns Hopkins University professor and former Bush administration official, wrote on Twitter, “I will oppose Trump as nominee. ... Short list: demagoguery, torture, bigotry, misogyny, isolationism, violence. Not the Party of Lincoln & not me.” He added that he has would support Clinton over Trump. [Twitter.com, 2/24/16, 2/24/16, 2/24/16]

RedState's Jay Caruso: “In Good Conscience I Will Not” Support Nominee Trump. Caruso, a conservative writer and RedState front-page contributor, listed “5 Reasons I Will Not Vote For Trump If He Is The GOP Nominee.” His reasons included that “Trump is not a conservative,” “He's lying to everybody on immigration,” “He's a crackpot,” “He has no class and he is no statesman,” and “He will do long term damage to the GOP.” [RedState.com, 1/1/15]

RedState's Ben Howe: “I Will Phone Bank For Hillary If Trump Is Nominated.” Howe wrote in a RedState post: “I will, should Trump win the nomination, work to make sure that the other dangerous and untrustworthy person, who has declared themselves to a representative of progressivism, takes the job.” [RedState.com, 1/12/16]

RedState's Neil Stevens: “I Will Never Support Donald Trump In An Election (Primary Or General).” Stevens, a RedState front-page contributor, cited “Cronyism and Property Rights,” “Morality and Character,” and “Birtherism and Conspiracy Theory” as among the reasons he would never vote for Trump in a primary or general election. [RedState.com, 1/22/16]  

Gun Blogger Bob Owens: “I Will Stay Home In November Before I Vote For Either Hillary Or Her Buddy Donald. It's Called Having A Moral Compass.” Owens is the editor of the pro-gun website BearingArms.com. [Twitter.com, 2/28/16]