Sure, Donald Trump had a disastrous week on the campaign trail, but at least he may have made history: Longtime political veterans say they cannot recall a candidate who has similarly and needlessly damaged himself quite so badly.

“I have been around politics for 40 years, as a journalist and a participant, and I have never seen anything like this last week,” said David Axelrod, President Barack Obama’s longtime aide and now a CNN commentator.

It’s not just Democrats who are amazed by the collapse. Underscoring the extent to which Trump’s campaign has bewildered political professionals, Republicans are also shaking their heads at their candidate’s indifference to basic campaign norms ― a strategy that worked in the primaries, but is proving disastrous in the election’s closing months.

“I don’t think we’ve ever seen anything quite like this,” said David Kochel, a former strategist for Mitt Romney and former Florida Gov. Jeb Bush’s presidential campaigns. “To have a candidate who reflexively takes the bait on any perceived slight, picks needless fights with his own party after the convention, constantly punches down and obsesses with his own cable news coverage is something we’ve never seen before.”

Trump has always been an asymmetrical candidate, flouting conventional wisdom in favor of a political style befitting a free-wheeling TV showman. But his past week has been a show featuring mainly self-immolation. He suggested that a Gold Star mother was not allowed to speak because of her Muslim faith, refused to endorse the speaker of the House ― a member of his own party ― for re-election, placed the onus on resolving the issue of sexual harassment in the workplace on the recipient of the harassment, and concocted, apparently out of whole cloth, a video of money being airlifted to Iran.

David Plouffe, Obama’s 2008 campaign manager, called these moments “being in the barrel”: a point in a campaign where a candidate simply cannot get beyond a cascade of bad press and controversy.

But to apply that aphorism to Trump’s past week might not do the barrel justice, veterans of past campaigns argue. Stuart Stevens, a top aide to Mitt Romney’s 2012 campaign and a frequent Trump critic, noted that other candidates have imploded before. No one, he argues, has done it quite as spectacularly and with such a large potential for damage as Trump.

“Donald Trump is Todd Akin. He is Richard Mourdock and Sharron Angle,” he said, referring to three infamous Republican Senate candidates who committed fatal verbal miscues. “But that is really not fair to Akin, Mourdock and Angle. They weren’t nuts. They had political views and others that made them unelectable. With Donald Trump, it is instability. He is an absurd candidate for president. He is a neutron bomb that has gone off in the Republican Party that is destroying anyone near him.”

ASSOCIATED PRESS Donald Trump has had a self-destructive streak that is comparable to Sharron Angle's 2010 Senatorial campaign.

Within some political quarters, there remains lingering faith that Trump still has the capacity to turn his free-fall around ― that his historically unparalleled bad week won’t leave enough lingering damage to cost him the election. But those voices are growing rarer. Trump’s poll numbers have tanked since the end of the Democratic convention, with traditionally Republican states like Georgia and Arizona looking more like pick-up opportunities for Hillary Clinton. Increasingly, there is chatter of discord within the ranks.

One GOP operative close to Trump compared his campaign to that of Carl Paladino, the Buffalo businessman who won the 2010 Republican nomination for governor in New York thanks to his outsider, anti-establishment, “politically incorrect” appeal, but then got clobbered in the general election. Paladino is now Trump’s New York State chairman.

“Same candidate model,” the operative said. “Will Trump meet his New York state director’s 2010 fate and be crushed at the polls because of all the stupid comments? Carl talked himself into total defeat.”

Douglas Brinkley, a presidential historian at Rice University in Houston, said he cannot remember as big a collapse since then-Kansas Sen. Bob Dole’s post-convention decline in the 1996 campaign. Brinkley expects Trump’s polling numbers will recover to some extent. But he added that polling is not Trump’s biggest problem.

“The big story in August is the defection of the Republican establishment from Trump. You are creating Hillary Clinton Republicans,” Brinkley said. “It’s going to be hard for Trump to win with that brain drain. ... It would have to be a complete collapse of the Hillary Clinton campaign for him to win.”

Anita Dunn, a longtime Democratic operative, said there was “no parallel” for Trump’s candidacy in terms of his temperament, approach to politics and propensity for self-immolation. “Nothing in any of our lifetimes.” But she did suggest that the closest comparison to the free-fall being witnessed right now was 1972, when George McGovern chose Tom Eagleton as his running mate and then had to withdraw the pick after it was revealed that Eagleton had been previously hospitalized for severe depression.

In that moment, McGovern’s candidacy seemed to fall apart under the assumption that he couldn’t get his own presidential ticket in order. But veterans of that campaign ― and others ― say it is not in the same vicinity as what’s happening in this cycle.

“If there is [a parallel], it escapes me,” said former Sen. Gary Hart, who managed McGovern’s campaign. “In terms of consequences both incidents may turn out to be the same, that is a reason for undecideds to decide. Without revisiting all the details of the Eagleton experience, Senator McGovern selected a trusted Senate colleague who was invited to reveal any personal matter that might be used against him, and he had won two statewide races without his medical condition being revealed. Today, I suspect it would be treated by the press and public much differently. Donald Trump has persisted in exhibiting demeaning, belligerent, nasty behavior that is also causing undecided voters to decide.”

Editor’s note: Donald Trump regularly incites political violence and is a serial liar, rampant xenophobe, racist, misogynist and birther who has repeatedly pledged to ban all Muslims ― 1.6 billion members of an entire religion ― from entering the U.S.