Cautiously optimistic — that’s how I feel about U.S. Attorney John Durham being put in charge of getting to the bottom of the failed FBI-Deep State coup against President Trump.

Maybe you’re pessimistic, concerned that the top federal prosecutor in Connecticut might turn out to be another one of these disappointments like Jeff Sessions’ boys from Chicago and Utah who haven’t really done any investigation of the investigators.

But look on the bright side. Close your eyes and think about where crooked G-man/gangster Zip Connolly is this morning — in a state prison in Florida, age 78, about 10 years into his 40-year sentence for an organized-crime hit.

I know, it’s a state bid, but Durham got the ball rolling in Boston, pinning a federal racketeering rap on him back in 2002.

Ya think any of those swamp creatures in D.C. are reading up on Durham’s curriculum vitae today? Anybody named Comey? Brennan? Clapper?

There was a lot of chatter on talk radio Monday about how the FBI framed the four guys in Boston in 1965 for a gangland murder in Chelsea they didn’t commit. Bob Mueller was briefly the acting U.S. attorney in the 1980s and he did nothing to get them out, even though literally everyone in the city knew the G-men had railroaded them, to protect, not Whitey Bulger, but a prized new snitch named Joe Barboza.

It’s all very involved, but here’s what matters today: The case against the four imprisoned innocent men started unraveling in the late 1990s. Hitman Johnny Martorano told the feds in Boston who had really killed the gangster Teddy Deegan (as if they didn’t know already!). Barboza had even told Martorano, and another guy named Dido, how he would frame the four innocent guys, which he then did.

John Durham had just been appointed to clean up the two generations of corruption in the Boston FBI office. He knew how corrupt the Boston agents were — Whitey’s partner Stevie Flemmi said last year under oath that they were paying off at least six local G-men. Some have speculated they may have had as many as 10 on the pad.

The cops were so corrupt that Durham set up shop at the federal courthouse in Worcester, so that … well, anything could have happened in Boston, right? It already had, over and over again.

Anyway, after the local prosecutors had Martorano’s testimony nailed down, they went to Durham. He’s the one who started the process of righting the terrible wrong of 35 years in prison after the FBI frame. It took years, but the four men or their estates ended up winning a civil judgment of $102 million.

(Mueller, by the way, was FBI director by then, and Judge Nancy Gertner had to threaten him with contempt of court to get the Bureau to finally release the exculpatory evidence that proved they had been framed. She called Mueller’s attempts to stonewall the court “chilling,” which was an understatement.)

Some have complained that Durham should have put more crooked G-men behind bars. But the statute of limitations was a problem, and Zip Connolly’s partner in crime, John “Vino” Morris, had cut a deal, even though he’d set up at least two guys to be whacked out by Whitey Bulger. (Maybe that’s why Vino got promoted to director of the FBI training academy in Quantico — this latest corruption by the G-men is just a continuation of the Bureau’s sordid history.)

Durham also took down a crooked state cop named Schneiderhan — maybe if this other gig doesn’t work out, we can get him back here to handle the latest “Troopergate.”

In his closing arguments in the Zip Connolly racketeering trial, Durham reminded the jury of the crooked fed’s first payoff — a stolen 2-carat $5,000 diamond ring his paymaster Whitey had given him.

I remember that story well. One day at the courthouse, I rode down to the lobby in the elevator with Zip. I started asking him, in real snarky terms, what his favorite song was by Gary Lewis and the Playboys?

“She’s Just My Style”? “Sure Gonna Miss Her”? “Everybody Loves a Clown”? “Count Me In”? “Save Your Heart for Me”?

I think Zip figured out where I was going with this line of patter, so just as the elevator door opened, I yelled at him:

“Oh no, Zip, I’ll bet your favorite Gary Lewis and the Playboys song is ‘This Diamond Ring.’”

He ran outside to the microphones and started screaming at the other reporters. It was maybe my favorite day ever on Northern Avenue.

I’d like to ride down an elevator in a federal courthouse with an indicted G-man one more time. If only John Durham comes through, I’m sure I could think of a lot of songs to ask, say, James Comey about.