Walt Nauta, Donald Trump’s Diet Coke valet-turned-personal aide, pleaded not guilty on Thursday to federal charges that he conspired with Trump to withhold classified documents. Nauta is facing five counts of concealing or withholding documents and conspiring to obstruct justice, a charge that could land him up to 20 years in prison. According to his indictment, Nauta is accused of moving numerous boxes containing the classified files under Trump’s orders, then lying to federal investigators about doing so. His arraignment Thursday was twice-delayed—Nauta asked for his first to be postponed because he still didn’t have a local Florida attorney lined up, and the rescheduled hearing last week was pushed back again after his flight to Miami was canceled.