Jury selection began Tuesday in the case against former Trump White House official Peter Navarro, who was charged with contempt of Congress after he refused to cooperate with a congressional investigation into the Jan. 6, 2021, attack on the U.S. Capitol.

Navarro, a former economics professor, served as a White House staffer under then-President Donald Trump and later promoted the Republican’s baseless claims of mass voter fraud in the 2020 election he lost. Navarro has said that Trump invoked executive privilege, barring him from cooperating with the House Jan. 6 committee. His trial is expected to last through the end of the week.

U.S. District Judge Amit Mehta has ruled Navarro’s executive privilege argument isn’t a defense against the charges, finding that Navarro hadn’t shown evidence Trump invoked it.