The extraordinary move by Trump to leave his chief of staff out of the most significant U.S. military operation against the world’s most wanted terrorist since the killing of Osama bin Laden in 2011 represents a major blow to Mulvaney, suggesting that he is increasingly sidelined inside the White House.

The White House chief of staff typically would be central to such a momentous gambit for a president, coordinating logistics, public statements and notifications of congressional leaders and allies. Bill Daley, who was White House chief of staff during the bin Laden raid, was seated next to then-President Barack Obama as he monitored the raid in a secure White House room with a small group of senior officials.

Andrew Card, former President George W. Bush’s longtime chief of staff, said the exclusion of Mulvaney from a moment of such magnitude in the presidency is difficult to grasp because the chief of staff typically would be in national security meetings leading up to it and tasked with coordinating with other top officials on everything from a communications strategy to a plan in case the raid failed.