A group Saudi Arabians opposed putting infidel American troops into Saudi Arabia prior to Gulf War 1, They are ignored and US troops go into Saudi Arabia. After Gulf War 1 the Americans don't leave. There are threats/warnings for Americans to get out and then escalating attacks against US targets culminating in the 9/11 attacks by a group of predominately Saudi Arabian terrorists. Terrorists who wanted American troops out of their home country. War is the continuation of politics by other means. Terrorism is a tactic. It is a form of guerrilla warfare. The original stated political goal was to get American troops out of Saudi Arabia.So yes American foreign policy thought up by our political elite was directly responsible for 9/11.