WASHINGTON – Barely two weeks after his resounding nomination as the Republican candidate for the presidency, Donald Trump’s series of political gaffes has created a panic among once-enthusiastic party figures, who now wonder what they have wrought for the GOP’s chances to regain the White House in November.

Trump’s call for a temporary ban on Muslims entering this country bought a sharp rebuke at the Democratic National Convention from the Muslim-American father of a U.S. soldier killed in Afghanistan.

Trump’s response that Khizr Khan, the father, had “no right” to criticize him only intensified the quarrel. Trump backers and strategists were appalled by the nominee’s continued aggressive behavior, and by the way it diverted his attention from the task of taking on Democratic nominee Hillary Clinton.

Trump’s easily avoidable personal clash with the Khan family was so offensive to key Trump endorsers such as House Speaker Paul Ryan, Sen. John McCain, former Speaker Newt Gingrich and New Jersey Gov. Chris Christie that they all voiced their disagreement or dismay.

When Trump first clinched the GOP nomination, Ryan had said he wasn’t “ready” to endorse him, although he subsequently did so. In apparent pique, Trump now said he wasn’t ready to endorse Ryan’s primary bid for re-election to the House. Whereupon Trump’s running mate, Mike Pence, in an obvious split, declared he strongly did so.

Trump’s campaign manager, Paul Manafort, recently brought aboard to bring order to the campaign and rein in the obstreperous nominee, finally reported that Trump was endorsing the speaker, the highest-elected Republican. But on a radio station in Green Bay, Wis., Ryan said his endorsement of Trump was “not a blank check,” and he stoutly defended the Gold Star family’s right to speak out.

By now there is widespread concern that the free-wheeling Trump is an unmanageable loose cannon on a path of political self-destruction. Gingrich, who earlier had said he was available to be Trump’s running mate and seemed increasingly to be campaigning for the job, has joined the criticism in harsh terms.

According to the Washington Post, Gingrich said the presidential race turns on “which of the two (candidates) is the more unacceptable. Trump is helping her (Hillary Clinton) win by proving he is more unacceptable than she is.”

He added: “Anybody who is horrified by Hillary should hope Trump will take a deep breath and learn some new skills. He can’t 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.”

Inevitably, a sense of buyer’s remorse appears to be setting in among some prominent Republicans such as National Chairman Reince Priebus, who bent himself into a pretzel upon Trump’s nomination by buying into it and hoping for the best.

Many of the old GOP establishment leaders who boycotted the party’s national convention – the two Presidents Bush, defeated challenger Jeb Bush and 2016 party nominee Mitt Romney – have already expressed remorse without ever having bought into Trump. They can be expected now to add their voices to the growing consternation.

Perhaps the last time a presidential nominee gave some in his party a serious case of regret was in 1976, when little-known former Georgia Gov. Jimmy Carter was closing in on the Democratic nomination. Two late entrants, young Gov. Jerry Brown of California and Sen. Frank Church of Idaho, challenged him in the remaining 11 primaries and between them won 8, but to no avail. Carter won 18 of 30 and the presidency.

In 1980, Democratic Sen. Ted Kennedy sought at the party convention to ignite a floor rejection of Carter seeking a second term, by freeing delegates pledged to him. The attempt failed, just as this year’s effort by anti-Trump forces to give pledged Trump delegates the chance to switch got nowhere.

So the Republican campaign featuring a non-politician turning the 2016 campaign into a three-ring circus goes on, no doubt with more unpredictable turns and conflict in the three-plus months ahead.