As head of the National Security Council (NSC) in the 1980s, Admiral John Poindexter became embroiled in scandal. He played a leading role in what came to be known as the Iran-Contra Affair, an illegal foreign policy campaign conducted by the administration of President Ronald Reagan. Poindexter inherited rather than started Iran-Contra, but he authorized its complex secret deals. As the controversy rocked the Reagan administration, Poindexter was fired, prosecuted, and convicted of five counts of providing false information to prosecutors and Congress. Later, however, he successfully appealed the conviction.

When Poindexter was chosen to head the NSC in 1986, Iran-Contra had been in operation secretly for several months. The NSC, an executive branch office that advises the president on foreign and domestic policy, had in 1985 begun exercising extraordinary power on its own. First, it had negotiated the sale of antitank weapons to Iran in hopes that the Iranian...