A politically connected state rep in Indiana was arrested on drunk driving charges after trying to buy “party favors” and pretending to be a member of law enforcement, police said.

Rep. Dan Forestal, an Indianapolis Democrat first elected in 2012, is facing charges of impersonating a public servant, operating a vehicle while intoxicated and resisting law enforcement in an encounter with police that started late Saturday in the parking lot of an Indianapolis hotel, the Indianapolis Star reports.

Cops responding to a report of a man impersonating law enforcement met Forestal, 36, as he tried to drive off from the Rodeway Inn, where the lawmaker initially complied with an officer’s request to show his hands before refusing to let go of the steering wheel, according to a police report.

After a “brief struggle,” the officers took Forestal into custody, at which point he threatened to sue them for violating his civil rights and identified himself as an Indianapolis firefighter and a state rep, as well as the nephew of the Marion County sheriff, police said.

Forestal, a 12-year veteran of the fire department, also threatened to “have” all of the officers’ badges as he swayed while he stood and had red, glossy eyes. He also refused to perform a field sobriety test, according to the police report.

Forestal later “attempted to rip” a warrant from an officer’s hand as he tried to take blood from the lawmaker at a hospital, prompting him to be placed in extra restraints.

The couple who initially called police, meanwhile, told investigators that Forestal had driven to their home earlier that night and identified himself as a “legit officer,” court documents show.

“I’m a legit officer doing a drug bust and today is the last day before the feds descend and start kicking in doors,” Forestal told the husband and wife, according to police.

The couple, James McGuire and Sheila Fennell, said they knew something was off right away.

“Just the way he approached us,” Fennell told WTHR. “I’ve never had an officer ever approach me like that.”

McGuire said Forestal didn’t introduce himself, but asked where he could find “people selling drugs” while flashing his fire department badge. Sensing something was off, McGuire snapped a photo of Forestal’s car and called police, he told the station.

It’s unclear why Forestal — whose fire department badge has since been confiscated — went to the couple’s home, the Indianapolis Star reports.

Cops also visited the bar where Forestal had been drinking earlier Saturday and a bartender said he had been harassing customers in search of “party favors such as cocaine,” WTHR reported, citing a police report.

Forestal’s attorney, Jim Voyles, declined to comment when reached by The Post, and a message seeking comment from Forestal’s legislative aide was not immediately returned early Thursday.