Washington (CNN) President Donald Trump's former attorney Michael Cohen confided a sense of isolation and anger to actor Tom Arnold weeks before the estranged Trump organization fixer reported to federal prison.

"The problem for me is I have nobody out there ... I'm a man all alone right?" Cohen lamented in a taped recording of a March conversation with Arnold obtained by CNN.

"I shouldn't be alone anymore after over 100 hours of testimony, right, including seven-and-a-half hours of being beaten up on national television, you know, international television," Cohen added.

For his part, Arnold -- a Trump critic -- reassured Cohen repeatedly throughout the tape and praised him for coming forward.

"You are going to prison," Arnold said. "I don't know exactly how long, but you have manned up and you're going to go to prison. And you could've gotten a pardon."

Cohen reported on Monday to a federal prison in Otisville, New York, for his three-year sentence.

Cohen recounts GOP attacks, olive branch for Gaetz

Cohen could be heard in the 36-minute long recording voicing his displeasure on a range of topics, including what he argued was over-the-top and even hypocritical treatment by Republicans since his public parting with Trump, his longtime employer.

"The Republicans were attacking me vociferously," Cohen said of his February appearance before the House Oversight Committee. "I mean, you would think that I had killed one of their grandchildren."

Cohen said he noted his previous role as a deputy finance chairman for the Republican National Committee, saying he told Republicans: "I said you didn't think I was this bad of a guy when I was out there raising $140 million for the RNC for vice chair right?"

Likewise, Cohen told Arnold he thought RNC Chairwoman Ronna McDaniel "was one of the worst people on the planet."

"She's just a bad human being," Cohen said. He was dismissed from the role last year.

RNC spokesperson Michael Reed said in response to CNN's inquiry that Cohen was a "proven liar" and disputed his claims of fundraising prowess.

"He is currently serving a prison sentence for lying," Reed said in an email. "The truth is, Cohen barely raised a dime for the RNC. He was lazy and untrustworthy. We hope the prison system does its job and he is able to emerge a better man."

Cohen did, however, seem to be past his anger with Florida GOP Rep. Matt Gaetz, who sent a tweet construed as threatening to Cohen that implied extramarital affairs before later backing off his claim. The tweet prompted a Florida Bar investigation, which CNN reported on Wednesday had advanced.

Cohen told Arnold he offered to send a letter on Gaetz's behalf to protect his law license.

"He apologized, you know, right afterwards," Cohen said. "Now, did he apologize because he was getting the crap kicked out of him by the press and you know, by people, you know, or did he do it because he actually has a heart?"

Arnold asserted, "Trump had him do it," to which Cohen said, "Of course he did."

'Never thought' he'd get a three-year sentence

The Wall Street Journal and Reuters previously reported on aspects of the tape.

The Journal noted in its initial report on the conversation that Cohen could be heard telling Arnold that he did not actually do some of the crimes included in his guilty plea. His attorney Lanny Davis told CNN at the time that nothing Cohen told Arnold "contradicts Mr. Cohen's previous defense attorney, Guy Petrillo, in his sentencing memorandum to" a federal judge last December.

Cohen indicated in the recording that he took the plea deal in part to protect his wife.

"You know what, I love this woman, and I'm not going to let her get dragged into the mud of this crap," Cohen said.

In the tape, as the Journal reported, Cohen was still reeling at the length of his sentence.

"I never thought the judge was going to throw a three-year fricking sentence," Cohen said.

At another point, Arnold compared Cohen to John Dean, a White House counsel to President Richard Nixon, whose testimony precipitated Nixon's resignation.

"Because John Dean -- people didn't know who John Dean was during Watergate," Arnold said. "We do now."

Arnold told the Journal that Cohen did not know he was being recorded.

A Trump loyalist turned opponent, political critic

Cohen has talked up his lengthy role at Trump's side, and shortly before reporting to prison on Monday, he said, "There still remains much to be told."

But outside of Trump's own distancing from Cohen in repeated tweets and criticism from Trump's lawyer Rudy Giuliani, at least one Trump Organization official has downplayed the significance of Cohen's role.

"He told Congress he was a 'fixer,'" Trump Organization vice president George Sorial wrote in an op-ed . "I'd put it this way: He was hired muscle; a bluffing, boasting New Yorker who could shock people into action."

In the recording, Cohen said he worked for Trump when the stakes were lower, confined largely to New York real estate, rather than global affairs.

"I always knew you know, who he was and what he was and so on, but it didn't really matter because he's a small microcosm of New York real estate," Cohen said. "It's very different when you start looking, to seeing what's happening now in the country — in the world you know."

He took issue in particular with Trump's openness to violent autocrats, including North Korean dictator Kim Jong Un and Saudi Crown Prince Mohammed bin Salman, who is accused of ordering the gruesome murder of journalist Jamal Khashoggi. Salman has denied ordering the killing, despite the conclusions of the US intelligence community.

"I'm not really sure why you'd want to be friends with them or even call somebody like that friends," Cohen said. "Uh, yeah. Charles Manson, he's my best friend. ... I want to go have dinner with Jeffrey Dahmer."

And while New York does not allow incarcerated felons to vote, the recording made clear who Cohen might back in 2020 given the chance against Trump -- a ticket with former Vice President Joe Biden and California Democratic Rep. Eric Swalwell.

"(Biden) is a good guy," Cohen said. "Problem is of course, is the age but then if you bring in an Eric Swalwell ... who has got a great look to him, he's young."