THE BURNED OVER DISTRICT

Donald Trump is taking all the elements of the Republican Party, taking out all the good and positive elements, and distilling the poisonous and hateful elements into a pure and concentrated party of vile bile. And lots of people are leaving the Republican Party because this is too far for them.

Now that Donald J. Trump is the presumptive presidential nominee, a parade of prominent Republican leaders is breaking with the traditions and rituals of party unity and offering him a blunt message:

Nope. Never. I can’t. I won’t.

In a flurry of social media posts and interviews over the last 24 hours, these Republicans raced to distance themselves from Mr. Trump, delivering a remarkable rebuke to him at precisely the moment when parties usually coalesce around a candidacy.

Mark Salter, a longtime strategist for Senator John McCain of Arizona, sounded resigned and disgusted as he said the unthinkable: He was now prepared to back Hillary Clinton.

“The GOP is going to nominate for President a guy who reads the National Enquirer and thinks it’s on the level,” he wrote on Twitter late Tuesday. “I’m with her.”

The dissenters, who range from wizened elders to younger strategists and even elected officials, are loudly and publicly proclaiming their unwillingness to support Mr. Trump.

Many have expressed reservations about him in the past, but left open the possibility they might back him in the future. Now they are forcefully foreclosing that option.

“I think Donald Trump has proven to be unbalanced and uniquely unqualified to be president. I won’t support him,” Stuart Stevens, the top strategist for Mitt Romney’s 2012 presidential campaign, said in an interview on Tuesday night. “Everyone has to make their own choice. I think Trump is despicable and will prove to be a disaster for the party. I’d urge everyone to continue to oppose him.”

Senator Ben Sasse of Nebraska, an up-and-coming Tea Party Republican many view as a future leader of the party, wasted little time disassociating himself from the current unofficial one.

Alluding to an essay he wrote in February, in which he denounced Mr. Trump as a destructive force bent on dividing the country, Mr. Sasse answered those who asked if Mr. Trump’s decisive victory in Indiana on Tuesday “changes anything for me.”

“The answer is simple,” he said: “No.”

Perhaps the most startling sentiments belonged to Republicans who said they would cross party lines to avoid elevating Mr. Trump.

A terse Twitter message, “#ImWithHer,” from Ben Howe, a contributing editor to the conservative website Redstate.com, immediately went viral. In a series of colorful follow-up posts, Mr. Howe despaired over the fate of his party with Mr. Trump as its nominee.

“Goodbye @GOP,” Mr. Howe wrote, adding: “I’m drinking wine directly out of the bottle right now. #NeverTrump.”

Steve Deace, a conservative radio show host in Iowa, said he would never waver from his pledge to oppose Mr. Trump to the end.

“You can sign my name in blood,” he wrote on Twitter.

Well, we did find out just how far some Republicans are willing to go.Next we will find out how many are left.