Nation Mick Mulvaney, new chief of staff, once called Trump ‘terrible human being’ December 15, 2018 Christal Hayes, USA TODAY Comments Off on Mick Mulvaney, new chief of staff, once called Trump ‘terrible human being’ Mick Mulvaney was tapped this week to replace Gen. John Kelly as acting chief of staff. As a congressman, he wasn't a fan of Donald Trump.