In studying the varying effects of terrorism on US foreign policy, the intent of the analysis presented in this paper was to glean lessons from America's past that may be applied in its future struggle against terrorism. Case studies included attacks in Beirut in 1983, West Germany in 1986, and New York and Washington in 2001. The study concluded that terrorism contributed to a complete failure of US policy objectives in Lebanon. Additionally, the American experience with Libyan terrorism, capped by the attack on the La Belle Discoteque in 1986, helped to first introduce military force as a realistic and credible US counterterrorism policy option. And the historic attacks of September 11 fundamentally changed the character and focus of a presidential administration and radically altered relations between the US and Russia, China, and Pakistan. Recommendations for future US policy included: maintaining a strong US presence in Afghanistan in order to prevent its use as a safe haven for terrorists in the future; carefully discriminating between policy issues that are important but separate from terrorism; acting preemptively and unilaterally against terrorists and their sponsors when necessary; and working to reduce the poverty, oppression, and other grievances that give rise to terror.