Robert Carl "Bud" McFarlane was an American Marine Corps officer who served as National Security Advisor to President Ronald Reagan from 1983 through 1985. Within the Reagan Administration, McFarlane was a leading architect of the Strategic Defense Initiative, a project intended to defend the US against Soviet ballistic missile attacks. He resigned as National Security Adviser in late 1985 because of disagreements with other administration figures but remained involved in negotiations with Iran and with Hezbollah.