Of all the bizarre narratives cascading from the Trump White House, perhaps the most disturbing and unsettling for anyone from New York or New Jersey who lived through the 9/11 attacks is how much Rudy Giuliani has changed.

America’s Mayor has become America’s Crazy Uncle.

Some of you will surely say that you saw this coming. And maybe you’re right. The signs were definitely there.

During his salad days as New York City’s mayor — and, before that, as a headline-grabbing federal prosecutor who helped to break up the mob — Giuliani displayed flashes of bellowing anger, infantile petulance, blind selfishness and callous heartlessness.

Remember his news conference to announce his divorce without telling his wife their marriage was over? Yep, that was Rudy in one of his nastiest moments. It almost seemed like the kind of thing that a headline-grabbing New York City developer at the time, Donald Trump, might have done.

Looking back now, some readers are also probably saying that, given what we knew about Giuliani back then, it was only a matter of time before he joined forces with the equally angry, petulant, selfish and heartless President Donald Trump. After all, the like-minded tend to find each other.

Even so, those occasional starbursts of weird bluster and scratch-your-head snarky behavior by Giuliani seemed to disappear — or perhaps were overlooked and forgiven — in those hard months after the deadly terrorist attacks on a Tuesday morning.

The right man for the moment

In the smoke-filled, fearsome days that followed Sept. 11, 2001, Giuliani seemed to be everywhere with the right words and tone.

In the hours after the attacks themselves, as the nation wondered what had really taken place and President George W. Bush was silent as he was shuttled on Air Force One to a locked-down Air Force Base in the Midwest, here was Giuliani, speaking as a sort of modern Greek chorus in voicing the nation’s grief.

“Today is obviously one of the most difficult days in the history of the city,” Giuliani said, only hours after the towers of the World Trade Center toppled in lower Manhattan.

"The number of casualties," he added," will be more than any of us can bear ultimately.”

The words were heartfelt, not heartless. More than other politicians that day, Giuliani captured the sense of despair and tragedy that had suddenly enveloped the nation. No wonder we dubbed him "America's mayor." He was just that.

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Weeks later, surrounded by New York City firefighters onstage for the opening of “Saturday Night Live,” here was Giuliani telling America it was OK to laugh again.

And we laughed. Of course we did. Giuliani seemed to be a man we could trust. He spoke for us.

“The attacks of Sept. 11th were intended to break our spirit. Instead we have emerged stronger and more unified,” he said months later at the opening of an exhibit of photographs from those attacks. “We feel renewed devotion to the principles of political, economic and religious freedom, the rule of law and respect for human life. We are more determined than ever to live our lives in freedom.”

Fast-forward, and now Giuliani is a regular character on "SNL." Once viewed as the nation’s conscience, Giuliani has morphed into a comic foil. No longer depicted as the post-9/11 voice of reason, Giuliani is portrayed by comedian Kate McKinnon as a sleazy nut job who is prone to crazy statements in defense of President Trump.

And people laugh this time, too.

Then it all came crashing down

Just as Giuliani’s calming words in the wake of the 9/11 attacks resonated with America, the comic portrayal of his descent into weirdness also resonates. America seems to know a nut when it sees one.

What happened?

Surely that is a fair and intriguing question now. Giuliani was never a fool. Nor was he considered stupid.

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And yet, how else to explain him.

A New Yorker article recently theorized that Giuliani, now 75, has “lost it mentally” and that historians may come to regard him as a “one-man wrecking crew” for the Trump administration.

In a recent CNN segment, Giuliani first denied that he asked the Ukrainians to investigate former Vice President Joe Biden, then quickly reversed himself and admitted that he actually had asked for such an inquiry.

“Of course I did,” Giuliani chortled, seemingly pleased with himself but also seemingly oblivious that he had just flip-flopped on his denial-admission — a flip-flop that may contribute mightily to the impeachment of his legal client, Donald Trump.

Such a convoluted style of thinking and speaking should not surprise anyone who has paid attention to Giuliani in recent years as he has grown closer to Trump.

Remember his pretzel logic on NBC News' “Meet the Press” in August 2018 that “truth isn’t truth”? Socratic scholars across the globe are still trying to unravel that one.

Or how about this mini temper tantrum recently on Fox News: “Shut up, moron. Shut up. Shut up.”

Yep, that’s our Rudy. It has been a long, slow slide in the 18 years since 9/11. In recent days, a satirical advertisement appeared on a New York subway train, mocking Giuliani's legal skills. "Need a lawyer? Call Crazy Rudy," said the ad, which featured a bug-eyed photograph of Giuliani.

Giuliani doesn't fight for us any longer

What’s troubling is that it’s not hard to remember that Giuliani’s leadership to curtail crime in New York and revitalize its dormant economy in the 1990s played a major role in resurrecting the city from its decades-long decline. Giuliani battled the porn hustlers in Times Square, the heroin junkies in Central Park and the oppressive “squeegee men” who wiped your car with dirty rags and demanded your spare change. And mostly, he won those battles.

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Under Giuliani, New York began to shed its reputation as a vortex of dysfunction. The city is hardly perfect now. But anyone who remembers the city of a quarter-century ago has to admit that New York has changed in ways that many back then never thought possible.

Worth remembering is that Giuliani was hardly perfect back then, either. During his eight years as New York’s mayor, which ended in December 2001, Giuliani slipped into moments of cartoon-like calamity. Sometimes his ego seemed as massive as Manhattan. Sometimes his statements on race and poverty seemed unkind. But few doubted his mental makeup.

Now that’s changed.

In the days after the 9/11 attacks, Giuliani was introduced by Oprah Winfrey during a prayer service at Yankee Stadium as the “man of the hour, a man whose extraordinary grace under pressure in the days since this devastating attack has led him to be called America's mayor.”

Rudy Giuliani is no longer a man of grace.

He’s the mayor who fell from grace.

Mike Kelly is a columnist for the North Jersey Record, where this column originally appeared. Follow him on Twitter: @MikeKellyColumn