This study addresses U.S. policy options to maximize deterrence of a nuclear armed Iran. It explores the possible stages of an Iranian nuclear weapons program and lists the desired objectives of U.S. deterrence policy with respect to Iran. It further explores on whom deterrence policies should be focused for maximum effect and what diplomatic, military and economic strategies the U.S. could employ to achieve those objectives. The paper looks at cooperative security agreements in the Persian Gulf region to bolster deterrence and recognizes and explores some limitations and constraints on U.S. policies following Iran's development of nuclear weapons.