sentences:  During Operation Desert Shield in 1990, US Defense Secretary Dick Cheney cited the landmark meeting between Roosevelt and Ibn Saud as one of the justifications for sending troops to protect Saudi Arabia's border.The Persian Gulf region was still regarded as an area of vital importance to the US during the Cold War.Three Cold War American presidential doctrines (the Truman, Eisenhower, and Nixon Doctrines) played roles in forming the Carter Doctrine.