'I think he went crazy': Trial lawyer reveals 'no one can explain' Rudy Giuliani

Former New York City Mayor Rudy Giuliani is already under criminal investigation by federal prosecutors. Yet, Giuliani maintains that he will prevail as the ultimate hero of the story.

In a Sunday panel discussion, two top legal minds, NYU Professor Melissa Murray and notorious trial lawyer Steve Susman discussed the strange pivot made by the mayor.

"I think he went crazy," Susman said of Giuliani's evolution over the years. "I know people used to respect him. He was America's Mayor. And I think -- my theory is that when men get to be over 75 ... they're in fear of becoming irrelevant. His was he's not going to be on any more afternoon talk shows. He was not going to be important anymore. So, you're looking for a way: how can you become relevant? And he became, I say, -- Trump talks about a deep state. There is a shadow state. He was a shadow Secretary of State, Rudy. We have a shadow attorney general. We have a lot of -- maybe Rudy was a shadow attorney general."

MSNBC host Ari Melber noted that Susman was talking about his legal peers and cohorts from his own age group.

"Some of them have not aged well in the sense of the service they're doing," said Melber.

"They are taking a risk -- risking their reputations that they have worked so hard to build up because they want to remain -- they're worried about not getting another phone call, not being part of something important," Susman continued. "That's the only thing I can figure out happened to him because he's totally -- no one can explain it, people who know him."

Melber noted that this leads to the question of intent for not only Giuliani but for President Donald Trump as well.

Murray prefaced her agreement by saying she didn't want to play an arm-chair psychologist but found the argument a compelling one.

"We did have a man who, in 2001, that was at the high of his powers, America's mayor presiding over one of the biggest counter-terrorism movements in history and now he's a failed presidential candidate," she explained. "He's working for the man that bested him as the Republican nominee for president, and he's eager to stay in the inner circle. I think it is a plausible theory."

Melber played remarks from a recent interview with Rep. Ilhan Omar (D-MN), who described Giuliani and Trump as mobsters.

"I do think that there is something to it," Susman agreed. "He's just -- he loves flying around first class around the world, going to capitals. He's treated like a government official. And that's the problem -- he's not a government official. I mean, it is like Trump allowing me to be Secretary of State or someone without being confirmed by the Senate. Who would want their government turned over?"

Melber noted that this past week, Giuliani was in Ukraine, he said, working on a "documentary" about his conspiracy theories that will appear on the fringe network OAN.

"I think he's trying to talk to potential witnesses against him, frankly," Susman suspected. "See what problems he's really having. Who is going to turn on him. That's what I think."

Watch the fascinating discussion in the video below: