President Donald Trump’s former acting White House chief of staff resigned his post as special envoy to Northern Ireland on Thursday, saying “I can’t do it. I can’t stay.”Mick Mulvaney joined a growing list of Trump administration officials who are leaving following the violent riot at the Capitol on Wednesday. He served as acting White House chief of staff from January 2019 until March 2020. I can’t stay,” Mick Mulvaney told CNBC, which was first to report the resignation. “Those who choose to stay, and I have talked with some of them, are choosing to stay because they’re worried the president might put someone worse in.”