President Donald Trump complained that he was not fully briefed before signing an executive order that gave chief political strategist Stephen Bannon a seat on the National Security Council, The New York Times reports. The executive order, which gave Bannon an unprecedented security role for a non-military adviser, was reportedly one of a series of orders crafted by Bannon and policy director Stephen Miller. Trump reportedly signed the order without fully understanding the power it would grant Bannon, and grew angry when he later learned the order’s full significance. Other White House staff, including Chief of Staff Reince Priebus have also reportedly expressed concern over what they viewed as a lack of checks on Bannon’s and Miller’s powers. Priebus has since drafted a 10-part checklist of steps and approvals an executive order must receive before it is signed into action, the Times reports. Bannon, the former head of alt-right website Breitbart, has been credited with some of the Trump administration’s most controversial moves, and reportedly told allies that he had a narrow time slot in which to push his own agenda in the White House before other advisers put a check on his influence.