The crescendo of panic among leaders of the GOP, whether politicians, strategists or donors, may be nearing its apex, as they are now expressing grave reservations about the results for the party if Donald Trump continues to evince the kind of erratic and tempestuous behavior that he has exhibited since winning his party’s nomination.

Two major issues for those distraught at the Trump candidacy: his public confrontation with the parents of dead U.S. Army captain Humayun Khan, which has dragged on for days, and Trump’s refusal to endorse House Speaker Paul Ryan and Sen. John McCain in an interview with The Washington Post.

Some examples of the GOP disenchantment with Trump include:

Republican National Committee Chairman Reince Priebus, who was painted as “very frustrated” and stressed trying to explain away Trump’s series of problematic public statements to donors and other party leaders. One GOP strategist commented, “It’s the totality of the week. The whole Khan thing kicking off the week was a concern to him, and then obviously all the other smaller issues were. He’s been going after this all week. The [failure to endorse Ryan and McCain] was like the cherry on the cake.” Priebus, a close friend of Ryan, apparently took the rather unusual step (for him) of confronting Trump:

Scott Reed, chief strategist for the U.S. Chamber of Commerce: “A new level of panic hit the street. It’s time for a serious reset.” He added, “If Trump decides he wants to go it alone, it is a lonely road.”

Former House Speaker Newt Gingrich, a major backer of Trump: “The current race is which of these two is the more unacceptable, because right now neither of them is acceptable. Trump is helping her to win by proving he is more unacceptable than she is … He cannot win the presidency operating the way he is now. She can’t be bad enough to elect him if he’s determined to make this many mistakes.” He told Fox Business News, “I would say in the last couple of weeks, he has been remarkably underperforming and we'll see whether or not he can take a deep breath and learn these lessons."

Henry Barbour, an RNC member and veteran strategist from Mississippi: “I’m pulling for him, but he’s not driving on the pavement. He’s in the ditch. I’m frustrated. There’s time to fix it, but there’s one person who can fix it. It’s up to him. Republican voters have empowered him to be our nominee and he’s the one who’s got to perform.”

Steve Duprey, an RNC member from New Hampshire:

People are more frustrated than they have been with past indiscretions. People are just going, “Can you believe this?”. . . Our nominee is losing opportunities to make the case why he should be elected instead of Mrs. Clinton and instead spending all of his time dealing with controversies of his own creation.

Another GOP consultant: “Every conversation you have with every campaign in America, the first question is: How do you deal with Trump? … The level of uncertainty with Trump just throws everyone off. It really hurts all of them. The Republican Party to him is like any kind of real estate deal. It’s all transactional. … He’s willing to burn the house down.”

According to The Washington Post, campaign chairman Paul Manafort rejected claims that senior Republicans were attempting to have an intervention with Trump by Gingrich, former New York mayor Rudy Giuliani and other Trump loyalists. Asked about that possibility on Fox News, Manafort said, “This is the first I’m hearing about that.”