Gary J. Byrne has devoted his life to serving his country, and risked it to do the same — as a member of the US Air Force, a uniformed White House Secret Service officer, and a federal air marshal.

And he believes it is his patriotic duty to do anything he can to prevent Hillary Clinton from becoming president of the United States.

As someone who guarded the Oval Office during the Clinton presidency, Byrne, in an exclusive interview with The Post, tells how he witnessed “the Clinton machine leaving a wake of destruction in just about everything they do.”

He says he has also seen Hillary’s “dangerous,” abusive, paranoid behavior.

“It’s like hitting yourself with a hammer every day,” Byrne, pounding a fist into his open hand, says of the former first lady’s explosive anger.

In his new book, “Crisis of Character: A White House Secret Service Officer Discloses His Firsthand Experience with Hillary, Bill, and How They Operate,” out Tuesday, Byrne makes no apologies for his anti-Clinton motivations.

“ ‘America first’ is in my blood,” he writes, sounding very similar to another presidential hopeful.

  Byrne says he wants Americans to “vote [their] conscience,” but pledges to make sure “they have all the information that they need.”

For one, he thinks the Clintons’ own behavior bred an immoral White House culture.

Byrne revealed to The Post during the interview that Clinton staffers used cocaine on the job.

“There were some drug issues,” Byrne says. “Some people would come in to work in the morning, and they were barely walking, they would drop stuff off at the office, and go to the restroom where they would come out minutes later happy as a clown.”

He also exposes the “jogging list” for the first time.

“In the beginning of his first administration, when President Clinton was jogging outside, women who were dressed as if they were going clubbing or working out, started showing up at the southeast gate,” Byrne explains. “The agents . . . would get the women’s names, and run them to see who they were. If the women wouldn’t cooperate, they would be ushered out of the jogging group.

“Agents … insinuated that this list was used by President Clinton to try to meet these women,” Byrne says.

The book details how the president had as many as three mistresses during the same time period, including former Vice President Walter Mondale’s daughter, Eleanor, whom Byrne once discovered “making out on the Map Room table” with Bill Clinton…. read more here