Across the federal government, the Trump administration has expanded leak investigations and revived the use of polygraphs in cases involving disclosures to the press. At the Pentagon, that approach has now reached the same institution where Defense Secretary Pete Hegseth previously threatened senior military officers over suspected leaks. What was once described as an angry warning is now an active investigation affecting dozens of personnel.
Pentagon leak probe expands from threat to mass testing
The Pentagon subjected roughly 50 members of the Joint Staff to polygraph tests in August as part of a leak investigation tied to media reporting on U.S. weapons stockpiles, according to The New York Times report published September 4, 2026, and later confirmed in part by CBS News. CBS reported that some of the highest-ranking military officials were included in the testing, while noting that not every senior officer was examined.
That development tracks directly with a conflict that surfaced publicly more than a year earlier. ABC News reported on April 25, 2025, that Hegseth had accused top military officers of leaking information and threatened then-Vice Chairman Adm. Christopher Grady and Joint Staff Director Lt. Gen. Doug Sims with polygraphs. The reported outburst came after Hegseth was angered by news coverage that he had planned a Pentagon briefing for Elon Musk on China, according to ABC News.
The broader leak investigation inside Hegseth’s orbit had already been formalized before the current round of tests. Reuters reported in April 2025 that a March 21 memo signed by then-chief of staff Joe Kasper requested an investigation into unauthorized disclosures of national security information and explicitly left open the possibility of polygraph testing. At the time, several Pentagon aides were placed on administrative leave as that inquiry widened.
The confirmed action is centered in Washington, where the Joint Staff is based and where the Pentagon’s senior civilian and military leadership work. Reporting from CBS News and The New York Times describes the polygraphs as focused on Joint Staff personnel, making the Washington-area national security apparatus the clear center of the current investigation.
What is not yet known is whether the testing extended beyond those personnel in a systematic way. The New York Times reporting, as summarized by other outlets, said the probe also touched personnel linked to U.S. Central Command, but the Pentagon has not publicly released a full list of who was tested, which offices were included, or how many civilians versus military officers were involved. CBS also reported that Gen. Dan Caine, the chairman of the Joint Chiefs of Staff, was not polygraphed.
That lack of detail fits a broader pattern around the Pentagon’s handling of leak inquiries under Hegseth. The Washington Post reported in July 2025 that White House officials had previously moved to halt some Pentagon polygraph efforts after concerns were raised by one of Hegseth’s advisers. The Pentagon, according to that report, declined to comment directly on the underlying polygraph reporting and said only that it would not discuss an ongoing investigation.
The immediate context for the current polygraph round is reporting on strained U.S. munition supplies during the Iran war. The New York Times reported that the testing followed a series of articles detailing diminished stocks of key weapons, including long-range missiles and Patriot interceptors. CBS similarly reported that the leak inquiry focused on disclosures involving sensitive information about the nation’s stockpiles of advanced weapons.
The administration’s broader posture toward leaks helps explain why the Pentagon response escalated. Reuters reported in April 2025 that the FBI had begun using polygraph tests in its own internal leak investigations, while the Justice Department had eased restrictions on seeking records and testimony from journalists in leak cases. That places the Pentagon effort within a government-wide campaign rather than an isolated internal dispute.
For the public, the practical meaning is narrower but significant. Pentagon personnel can expect tighter controls on internal information sharing and more aggressive internal scrutiny while the investigation remains active, based on the reporting from CBS, Reuters and The Washington Post. What remains unconfirmed is whether the inquiry will produce disciplinary action, criminal referrals, or policy changes beyond those already described by Hegseth when he announced a joint Pentagon-Justice Department task force in July 2026 focused on identifying and prosecuting suspected leakers.