Manafort challenged Special Counsel Robert Mueller's authority to bring these charges. In a May 4 hearing on the challenge, Ellis repeatedly suggested that the prosecutors were not really interested in prosecuting the charges but had filed them to exert pressure on Manafort to cooperate with the special counsel's investigation into Trump. Ellis said he would rule on Manafort's challenge at a later date. On June 26, 2018, Ellis issued an opinion stating that "upon further review" the Mueller investigation had acted within its authority, clearing the way for Manafort's trial to proceed.