Winning a Supreme Court case can be like winning a championship football game without cheating.

It’s exciting and thrilling, but Robert MacLean said he isn’t planning on visiting Disneyland anytime soon.

Instead, the former federal air marshal is returning to the much less glamorous Merit Systems Protection Board (MSPB) to win back his job.

MacLean, of Ladera Ranch, Calif., has become one of the federal government’s most notable whistleblowers. His actions to warn the flying public about terrorist threats drew retaliation from the Department of Homeland Security (DHS). It fired him. He fought back. After a long legal road, MacLean was the first to test the Whistleblower Protection Act before the Supreme Court. He beat the Obama administration with a solid 7-to-2 decision Wednesday.

The administration, which in many ways has supported federal whistleblowers, wasn’t trying to overturn the law. But it did support MacLean’s firing. Had government lawyers won, the ramifications could have stretched far beyond MacLean’s situation. Federal agencies would have been able to gut provisions of the law that protect whistleblowers from reprisals by their bosses.

Now the case goes back to the MSPB, which had ruled against MacLean.

The Supreme Court victory meant Mr. MacLean is eligible for Whistleblower Protection Act coverage,” said Tom Devine, legal director of the nonprofit Government Accountability Project, which represents MacLean. “Now the MSPB must decide if he deserved it.”

That depends, Devine explained, whether the MSPB finds MacLean “reasonably believed his disclosure was evidence of a substantial and specific danger to public health or safety.”

Devine and MacLean are confident the MSPB will rule in their favor this time.

“I would love to go back into federal law enforcement,” ­MacLean said.

Unable to find employment in his profession, he currently is working in home building and remodeling, including demolitions, “pretty much the dirty end of construction,” he said.

MacLean said he felt vindicated at various steps along the way and did not doubt his ultimate victory.

“I’ve always felt good that our justice system would do the right thing,” he said.

The case hung on whether ­MacLean’s unauthorized disclosures about a potential plot to hijack airplanes were “specifically prohibited by law.”

Chief Justice John G. Roberts Jr. was succinct in his majority opinion: “The answer is no.”

A little background: In July 2003, DHS’s Transportation Security Administration (TSA) warned all air marshals, including MacLean, about the threatened hijacking. A few days later, the TSA temporarily canceled overnight missions from Las Vegas, where MacLean was based, to save on hotel bills. Rightly thinking this was foolish and dangerous, MacLean complained to a supervisor and the agency’s inspector general.

That went nowhere, so he leaked the information to MSNBC. The resulting outcry led the TSA to reverse its decision within 24 hours. When Mac­Lean’s identity was discovered in 2006, he was fired for revealing “sensitive security information.”

The administration incorrectly claimed those disclosures were prohibited by law. The disclosures were prohibited by agency regulations, which the government said had the force of law. That might sound like a picky difference, but the distinction is important. Employees are protected from reprisals, such as being fired, if the law does not prohibit their disclosures about “a substantial and specific danger to public health or safety.”

Had the government’s interpretation of what constitutes law prevailed, that “could defeat the purpose of the whistleblower statute,” the Supreme Court ruled. It would have allowed agencies to establish regulations “that ‘specifically prohibited’ whistleblowing.”

The administration argued that allowing employees such as MacLean to be covered by whistleblower protections would “gravely endanger public safety.” Yet it was the ill-considered and quickly reversed TSA decision to cancel overnight air marshal assignments that put the public in danger in the first place. Nonetheless, the court’s majority said, the administration’s “concerns are legitimate.”

DHS spokesman S.Y. Lee said that although the department is “disappointed in the outcome of the case,” it is “gratified that the Chief Justice and six other justices recognized that the policy implications of the decision raise legitimate security and safety concerns.”

Legitimate concerns, yes. But not strong enough to allow the administration to define regulations as law.

The Office of Special Counsel, which protects whistleblowers, told the court that an administration victory in this case would have generated a “grave concern . . . that agencies could abuse their regulatory power to over-designate the information that is to be prohibited from disclosure as a means of suppressing a broad swath of information and stifling whistleblowers. Likewise, agencies may selectively enforce such broad regulations to punish and deter whistleblowing. This danger is not far-fetched. After all, whistleblower protection laws exist because government officials do not always act in the nation’s best interests.”

The decision to cancel air marshal assignments was a good example of that.

Twitter: @JoeDavidsonWP

8Previous columns by Joe Davidson are available at wapo.st/JoeDavidson.