Pete Hegseth, the US Secretary of War, is reported to have waged a sustained pressure campaign against Army Secretary Dan Driscoll, culminating in Driscoll's resignation after he told President Trump that Hegseth's interference had left him unable to carry out military reforms. The rivalry, described by four sources as increasingly petty and vindictive, is significant because it exposes deep dysfunction at the top of the US defence establishment and has strained Hegseth's relationship with Vice President JD Vance, a long-standing friend of Driscoll's.

Driscoll's close friendship with Vance, dating back to their time at Yale in 2011, was reportedly the reason he secured the Army post, a fact said to have unsettled Hegseth from the outset. Tensions escalated when Trump bypassed Hegseth to have Driscoll help negotiate an end to the Russia-Ukraine war, and further flashpoints emerged, including leaked details of donations by Driscoll's wife to a Democratic congresswoman, a photograph of Driscoll jogging with a Democratic congressman, and public attacks from influencer Laura Loomer accusing Driscoll of incompetence. The Pentagon has separately been probing internal leaks, including polygraph tests on Joint Staff members, though the Department of War denies Hegseth's team was involved in targeting Driscoll. Trump had offered to let Driscoll remain until the midterms, but he chose to step down sooner, thanking Army soldiers in his resignation statement.