Former White House communications director Anthony Scaramucci argued Tuesday that President Trump’s biggest gaffe in the White House was his decision to make former Republican National Committee Chairman Reince Priebus his chief of staff.

“The biggest mistake that the president made in his presidency was his first hire,” Scaramucci told CNN. “When he hired Reince Priebus, who didn’t really like him, who tried to stop him from getting the nomination … he flooded the zone with [Republican National Committee] staffers.”