Dan Caldwell, a senior adviser to U.S. Defense Secretary Pete Hegseth, was removed from the Pentagon on Tuesday after being implicated in an investigation into unauthorized leaks from the Department of Defense, according to a U.S. official.
Caldwell was placed on administrative leave for what the official described as “an unauthorized disclosure.” The official did not elaborate on what information was allegedly disclosed or to whom, and said only that the investigation remains active.
A memo dated March 21 and signed by Hegseth’s chief of staff, Joe Kasper, called for a formal inquiry into “recent unauthorized disclosures of national security information involving sensitive communications.” The document also mentioned the potential use of a polygraph, though it is not clear whether Caldwell was subjected to one.
While not widely known to the public, Caldwell has been a key figure behind the scenes, advising Hegseth on major policy issues. His role gained attention after The Atlantic published a leaked Signal message thread last month in which Hegseth identified Caldwell as the primary staff contact for the National Security Council during preparations for U.S. strikes on Houthi targets in Yemen.
