Gates was implicated in the Iran-contra scandal

He was not indicted by special counsel Lawrence Walsh. But Walsh in his report devoted a chapter to Gates and concluded:

Independent Counsel found insufficient evidence to warrant charging Robert Gates with a crime for his role in the Iran/contra affair. Like those of many other Iran/contra figures, the statements of Gates often seemed scripted and less than candid. Nevertheless, given the complex nature of the activities and Gates's apparent lack of direct participation, a jury could find the evidence left a reasonable doubt that Gates either obstructed official inquiries or that his two demonstrably incorrect statements were deliberate lies.