For top Long Island politicos, 2016 could prove to be the year of living dangerously.

One sign arrived Dec. 4 when Nassau’s chief deputy county executive, Rob Walker, confirmed in public that he was under federal investigation.

Walker was testifying under an immunity deal as a witness against ex-State Sen. Dean Skelos and Skelos’ son, Adam, who were both since convicted of conspiracy, bribery and extortion.

As Newsday reported, federal officials have been reviewing a $12 million storm cleanup contract won by an Island Park company that donated to Walker’s Hicksville Republican Committee.

“What is your understanding of what your immunity order provides?” a federal prosecutor asked Walker on the stand.

“Anything I say in the courtroom, as long as I do not perjure myself, cannot be used against me,” Walker, a former state assemblyman, replied.

Now we await word whether that probe by U.S. Attorney Robert L. Capers will produce charges. Through his lawyer, Walker has denied all wrongdoing.

Walker may not be alone in Nassau’s 2016 danger zone.

Questions linger about why Walker’s boss, Nassau County Executive Edward Mangano, told prosecutors he was ready to invoke his right against self-incrimination if called to testify at the Skelos trial.

Ultimately, Mangano did not take the stand.

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Even if Mangano avoids legal problems in 2016, consider the political hazards.

Mangano has yet to tell county constituents what could have led their top elected executive to consider taking the Fifth.

Imagine how this might play in a campaign debate if he runs again in 2017.

Suffolk County has its own danger zone.

U.S. District Judge Leonard Wexler, in a stunning move, recently ordered James Burke, formerly the top uniformed officer in the Suffolk police department, held without bail.

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Burke stands accused of assaulting a burglary suspect — and orchestrating a cover-up of his role.

“There is no way he can be supervised to the degree where he’s not a danger to the community,” Wexler said in denying Burke’s release.

Suffolk County Executive Steve Bellone promoted Burke, who was widely known to be mentored by District Attorney Thomas Spota.

With federal prosecutors saying at least 10 unnamed Suffolk police officers are cooperating in the case, the political fallout may just be starting. FBI Assistant Director-in-Charge Diego Rodriguez said after Burke’s arrest: “We vow never to forget our obligation to remove from the criminal justice system those who don’t uphold the tenets of the legal system.”

Before his indictment last year, ex-Sen. Skelos told his son in a phone call recorded by the FBI: “Right now we are in dangerous times, Adam.”

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With Skelos now gone from office, other Long Island officials stand to find out how prescient he had been.