OK, having read the abstract and the majority opinion, two more comments:
The opinion's recitation of facts fleshes out the situation a bit (paragraph breaks added):
On July 26, 2003, the Department of Homeland Security (DHS) issued a confidential advisory about a potential hijacking plot. The advisory said that members of the terrorist group al Qaeda were planning to attack passenger flights, and that they “considered suicide hijackings and bombings as the most promising methods to destroy aircraft in flight, as well as to strike ground targets.” App.16.
The advisory identified a number of potential targets, including the United Kingdom, Italy, Australia, and the east coast of the United States. Finally, the advisory warned that at least one of the attacks “could be executed by the end of the summer 2003.” Ibid.
The TSA soon summoned all air marshals (including MacLean) for face-to-face briefings about the hijacking plot. During MacLean’s briefing, a TSA official told him that the hijackers were planning to “smuggle weapons in camera equipment or children’s toys through foreign security,” and then “fly into the United States . . . into an airport that didn’t require them to be screened.” Id., at 92. The hijackers would then board U. S. flights, “overpower the crew or the Air Marshals and . . . fly the planes into East Coast targets.” Id., at 93.
A few days after the briefing, MacLean received from the TSA a text message cancelling all overnight missions from Las Vegas until early August. MacLean, who was stationed in Las Vegas, believed that cancelling those missions during a hijacking alert was dangerous. He also believed that the cancellations were illegal, given that federal law required the TSA to put an air marshal on every flight that “present[s] high security risks,” 49 U. S. C. §44917(a)(2), and provided that “nonstop, long distance flights, such as those targeted on September 11, 2001, should be a priority,” §44917(b). See App. 95, 99, 101.
MacLean therefore asked a supervisor why the TSA had canceled the missions. The supervisor responded that the TSA wanted “to save money on hotel costs because there was no more money in the budget.” Id., at 95. MacLean also called the DHS Inspector General’s Office to report the cancellations. But a special agent in that office told him there was “nothing that could be done.” Id., at 97.
Unwilling to accept those responses, MacLean contacted an MSNBC reporter and told him about the canceled missions. In turn, the reporter published a story about the TSA’s decision, titled “Air Marshals pulled from key flights.” Id., at 36. The story reported that air marshals would “no longer be covering cross-country or international flights” because the agency did not want them “to incur the expense of staying overnight in hotels.” Ibid. The story also reported that the cancellations were “particularly disturbing to some” because they “coincide[d] with a new high-level hijacking threat issued by the Department of Homeland Security.” Id., at 37.
After MSNBC published the story, several Members of Congress criticized the cancellations. Within 24 hours, the TSA reversed its decision and put air marshals back on the flights. Id., at 50.
The court's decision hinged on their determination that the TSA was trying to give certain internal regulations the force of law when Congress had specifically not authorized them to do so. Under the Whistleblower Act, a government employee is protected from punishment revealing “any violation of any law, rule, or regulation,” or “a substantial and specific danger to public health or safety”
unless that specific disclosure is prohibited by law. The TSA fired McLean by claiming he broke a law that prohibited him from disclosing the information that he gave to the reporter.
The Congress, in the Homeland Security Act, authorized the TSA to write regulations concerning the disclosure of sensitive information, but the SCOTUS determined that Congress specifically and deliberately did NOT give force of law to those regulations and rules. The law itself does not specify any particular information that should not be disclosed. In other areas, the Congress did repeatedly give force of law to regulations and rules promulgated by the TSA by mentioning them in the authorization ("law, regulation, or rule"); but not in the particular section concerning sensitive information. So McLean's activity was protected under the Whistleblower Act.
McLean won at the Federal Circuit level as well. So I suppose now the TSA has to make good on the pay he would have received had he not been illegally fired?