Sen. John Fetterman has opened up about his “lonely” experience being a rare moderate Democrat in Congress willing to publicly break ranks from his party during partisan fights.

The Pennsylvania pol contended that Democrats have deviated from their values on issues such as government shutdowns, as well as border security, leading him to take his own path.

“I’ve, you know, had to vote against the caucus,” the sweats-loving senator told “Real Time With Bill Maher” on Friday. “I don’t enjoy that, but we used to be a party that would always refuse to shut the government down.

“And now we have shut it down and dropped a lot of mass chaos, and I just couldn’t be a part of that.”

Last week, Fetterman penned a defiant Washington Post op-ed declaring that he won’t ditch the Dems to become a Republican, insisting he’d make a “terrible” GOPer.

The Keystone State Democrat has been subject to a quiet recruiting campaign by Republicans to flip him and pad their Senate majority. A recent Politico piece about that whisper campaign sparked panic among some Democrats and prompted Fetterman’s op-ed.

Fetterman ran for Senate to much fanfare in 2022, becoming a darling of the left as he painted Republican Senate foe Dr. Mehmet Oz a carpetbagger and made use of a snarky social-media strategy while recovering from a stroke.

He is the last Democrat to have flipped a Senate seat from Republicans.

In addition to publicly bashing his party at times and punching the left, Fetterman broke ranks to back GOP Secretary of Homeland Security Markwayne Mullin’s nomination and oppose War Powers Act resolutions to rein in President Trump’s ability to attack Iran.

Still, despite his reputation for bucking the progressive left on issues, including over Israel, Fetterman is ideologically to the left of about a third of the Senate Democratic caucus, according to an analysis from GovTrack.

“I’m a committed Democrat,” Fetterman insisted to Maher.

“I thought we were supposed to be a big-tent party,” he said, referring to the Dems’ past perception as a group of inclusion.

“I’m not really sure how I have become an issue for any of the Democrats, just having some different views in these other issues.”

The Pennsylvania senator also dinged his party for espousing an “anti-men” sentiment that has led to the party’s hemorrhaging of young male voters.

“Part of the Democratic Party became more and more anti-men, or describing that they were part of the problem, or they have toxic traits and for those things, and that’s why there’s been such a migration away from the Democratic Party, from young men,” the senator said.

In his op-ed, Fetterman was adamant that he’s still a Democrat.

“My values have not changed, and I have always turned to those kinds of ideals that defined being a Democrat,” he wrote. “I remain strongly pro-choice, pro-weed, pro-LGBT, pro-SNAP, pro-labor and even pro-rib-eye over bio slop.

He said that if he ever switched to the GOP, “I’d be a terrible Republican who still votes overwhelmingly with Democrats.”