New Jersey’s top lawman on Thursday ordered a federal criminal investigation into crippling George Washington Bridge lane closures orchestrated by two of Gov. Chris Christie’s top appointees as an act of political revenge.

The state’s US attorney, Paul Fishman, will conduct a full probe of the Sept. 9-12 blockage of two of three Fort Lee lanes to “determine whether a federal law was implicated.”

The Christie administration may have violated laws related to interstate commerce, obstruction of justice and political intimidation, experts said.

Christie — a former US attorney — apologized for the scandal and said he has “nothing to hide.”

David Wildstein, his Port Authority appointee who cooked up the traffic mess, took the complete opposite approach.

First he went before a judge on Thursday in a desperate bid to quash the Assembly subpoena but was told he had to face the music.

Once sworn in, Wildstein invoked his Fifth Amendment rights against self-incrimination more than 20 times — even for the most innocuous questions. Frustrated lawmakers said his dodging was in “contempt” of the committee, and he could face a misdemeanor criminal charge.

Providing only his name and the town where he lives — Montville, NJ — Wildstein remained silent for most of the proceeding, refusing to answer questions about where he worked and whether a message with his name on it was an e-mail or a text.

“On the advice of counsel, I assert my right to remain silent,” Wildstein said over and over, with his lawyer whispering beside him. When he got tired of repeating that, he told committee members, “Same answer, sir.”

The state Assembly members said the contempt charge will be referred to law-enforcement authorities.

“I’m coming to the conclusion that I’m wasting my time in asking these questions,” said committee Chairman John Wisniewski, the Assembly’s deputy speaker.

Wildstein, a childhood friend of Christie, was on the receiving end of an e-mail from one of the governor’s aides that said, “Time for some traffic problems in Fort Lee.”

“Got it,” replied Wildstein, who resigned last month.

In New York, lawmakers demanded separate hearings on the traffic-jam scandal.

“While these reckless actions were committed exclusively by New Jersey political appointees, New Yorkers’ stake in the effective governance of the Port Authority is beyond questions,” said state Sen. Adriano Espaillat, who represents the northern Manhattan bridge communities of Inwood and Washington Heights.