(Bloomberg Opinion) -- Senator Mitt Romney was perplexed on Tuesday night.

“I can’t understand why the President would, once again, disparage a man as exemplary as my friend John McCain: heroic, courageous, patriotic, honorable, self-effacing, self-sacrificing, empathetic, and driven by duty to family, country, and God,” Romney wondered on Twitter.

Really? Just three years ago, Romney had more clarity.

“I’m far from the first to conclude that Donald Trump lacks the temperament to be president. After all, this is an individual who mocked a disabled reporter, who attributed a reporter’s questions to her menstrual cycle, who mocked a brilliant rival who happened to be a woman due to her appearance, who bragged about his marital affairs, and who laces his public speeches with vulgarity,” Romney said back then. “Think of Donald Trump’s personal qualities. The bullying, the greed, the showing off, the misogyny, the absurd third grade theatrics.”

So, no, it’s not hard to discern why Trump engages in rapid-fire, relentless mudslinging: The president of the United States is mean-spirited and insecure (and, of course, Romney knows that). This didn’t just surface this week, either. Trump has spent decades aiming his slingshot at everyone around him.

There was the late Leona Helmsley, an acid-tongued competitor in the New York real estate market, for example. “She is a living nightmare and to be married to her must be like living in hell,” Trump observed in Playboy magazine in 1990. “She’s out of her mind. Leona Helmsley is a truly evil human being.”

Helmsley was a tough businesswoman who reveled in mutual slagging, but Trump poured bile on many others in years past as well (diatribes that often also trafficked in sexism or racism). Olympic skater Katarina Witt was someone “with a bad complexion who is built like a linebacker.” His own partners on a Manhattan hotel property, the Pritzker family, were running “a racketeering enterprise.” New York Congressman Jerry Nadler was “one of the most egregious hacks in contemporary politics.” Bill Bradley, a former senator, was “as phony as a twenty-dollar Rolex.” Former AIG chairman Hank Greenberg was “scum,” and Lowell Weicker, a former Connecticut governor, was a “fat slob.” A Scottish landowner living near one of Trump’s golf courses was a “loser” whose home was a “disgusting blight on the community.”

The only difference between then and now is that Trump has become the most powerful man in the world, the Insulter-in-Chief, and social media has given him a platform to spout nasty 24/7 in front of a live audience. (The New York Times has tallied several hundred of Trump’s Twitter insults and, full disclosure, I appear on that list as a “dumb guy with no clue,” a “really stupid talking head,” and a “dopey writer.”)

Folks like me are fair game for Trump. So are guys like George Conway, a lawyer who is also the husband of a senior Trump adviser, Kellyanne Conway. Conway has been a persistent critic of the president and after Trump fired off an unhinged series of Twitter rants last Sunday, Conway took to Twitter to share excerpts from the “Diagnostic and Statistical Manual of Mental Disorders” – including pages describing “antisocial personality disorder” and “narcissistic personality disorder.” Well, that certainly set up Conway for the full-Helmsley-treatment and Trump deployed some of the same language he used 29 years ago when he pounced on Conway on Wednesday.

“George Conway, often referred to as Mr. Kellyanne Conway by those who know him, is VERY jealous of his wife’s success & angry that I, with her help, didn’t give him the job he so desperately wanted,” Trump allowed on Twitter. “I barely know him but just take a look, a stone cold LOSER & husband from hell!”

Then there are public servants, like the late Senator John McCain, who don’t deserve Trump’s venom yet find themselves, even in death, being treated like a pinata by the president. And there is much to speculate about when considering why Trump has insulted McCain so frequently over the last week. It may be an odd brew of Trump, who secured five draft deferments during the Vietnam War, permanently resenting McCain, a highly decorated POW who fought in the same war; Trump, disgusted with McCain’s vote to block the president’s attempted repeal of the Affordable Care Act; Trump, suspicious of McCain’s role in sharing information with federal investigators probing possible ties between the Trump presidential campaign and Russia; Trump, unable to form strong friendships, jealous of McCain’s easy bonhomie and of the widespread praise that poured out for the late senator at a funeral the president wasn’t invited to attend.

Nobody but Trump knows the full scope of his enmity, but McCain’s funeral was the centerpiece of his most atrocious insult of the week, which he popped off during a visit to an Ohio factory on Wednesday.

“I gave him the kind of funeral he wanted, which as president I had to approve,” Trump said of McCain’s funeral even though it didn’t actually require his approval. “I don’t care about this, I didn’t get a thank you, that’s okay. We sent him on the way. But I wasn’t a fan of John McCain.”

Trump’s fuming drew criticism, and much of it lacked Romney’s wonderment. A former McCain adviser and speechwriter, Mark Salter, took the funeral comments in stride. “Had you been a fan, the Senator would have wondered what he had done so wrong that he earned the approval of a man he despised,” he tweeted at Trump.

That was in keeping with comments from Senator Johnny Isakson, a Republican, who came to McCain’s defense repeatedly recently and didn’t hesitate to criticize Trump in interviews. “I just want to lay it on the line, that the country deserves better, the McCain family deserves better, I don’t care if he’s president of United States, owns all the real estate in New York, or is building the greatest immigration system in the world,” he told The Bulwark, a recently launched conservative publication. “Nothing is more important than the integrity of the country and those who fought and risked their lives for all of us.”

Trump’s barrage of insults – accompanied by the constant drumbeat of “loser, loser, loser” – may have lost some of the easy traction of his early days in the Oval Office.  To be sure, some, like Senator Lindsey Graham, still hesitate to respond forcefully to Trump even when he attacks old friends and colleagues. Others, like Kellyanne Conway, choose to take the president’s side in the insult wars, even when one of Trump’s targets is her own husband. But Isakson, and some members of the U.S. business community, are comfortable ignoring or challenging the example Trump sets, the demands he makes, or the insults he hurls.

That dynamic may not last, but for the moment, McCain’s supporters are on the right side of history and showing others how, amid the chaos and the insults, they can still respond to the better angels of their nature.

To contact the author of this story: Timothy L. O'Brien at tobrien46@bloomberg.net

To contact the editor responsible for this story: Matthew Brooker at mbrooker1@bloomberg.net

This column does not necessarily reflect the opinion of the editorial board or Bloomberg LP and its owners.

Timothy L. O’Brien is the executive editor of Bloomberg Opinion. He has been an editor and writer for the New York Times, the Wall Street Journal, HuffPost and Talk magazine. His books include “TrumpNation: The Art of Being The Donald.”

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