A senior advisor to Defense Secretary Pete Hegseth has been placed on administrative leave amid an investigation into unauthorized disclosures from within the Pentagon, according to a Defense Department official. Dan Caldwell was escorted out of the building and suspended after being linked to an alleged leak. Caldwell, a foreign policy realist, previously worked with restraint-oriented groups Defense Priorities and Concerned Veterans for America and has publicly argued for reducing U.S. troop deployments in Europe and withdrawing forces from Iraq and Syria.
The Pentagon recently announced a broader effort to identify the source of recent leaks involving sensitive national security information. In a memo, DoD Chief of Staff Joe Kasper said the department would use polygraph exams consistent with law and policy. The investigation will culminate in a report to the defense secretary detailing unauthorized disclosures and recommending improvements, with any identified leaker potentially referred for criminal prosecution. Caldwell’s close ties to Hegseth were highlighted in a leaked Signal chat regarding U.S. strikes on the Houthis, which became public after National Security Advisor Mike Waltz mistakenly added a journalist to the group.
The leak probe comes amid heightened tensions over reporting on U.S. strikes against Iran. President Trump has sharply criticized media coverage of a preliminary intelligence assessment suggesting limited impact from bunker-buster bombs, blaming leaks for undermining the operation. At a Pentagon press conference, Hegseth and Joint Chiefs Chairman Gen. Dan Caine pushed back, emphasizing that the assessment was preliminary, low-confidence, and acknowledged likely severe damage.