to a UCLA history professor, Saudi Arabia recently has become much more active in terms of foreign and security policy for three reasons: the Arab uprisings of 2010 and 2011, the policies of the Obama administration and the collapse of oil prices. History After World War II (1939–1945) and during the Cold War (–1991), Saudi Arabia maintained an anti-Communist, anti-secular Arab-nationalist policy, often working with the leading anti-communist power, the United States. Following the 1973 oil crisis, when Saudi Arabia and other Arab oil exporters embargoed the United States and its allies for their support of Israel, oil revenues increased dramatically, and the Kingdom worked to become the leading Islamic state, spending generously to advance Islam and particularly its conservative school (known as Wahhabism). Supporters see this as having purified and unified the Islamic faith; other commentators claim it has eroded regional Islamic cultures. (Examples of the acculturizing effect of Saudi aid can be seen among the Minangkabau and the Acehnese in Indonesia, as well as among the people of the Maldives. The Wahhabi form of Islam is also perceived in the West as a source of Islamist extremism. Saudi Arabia and its oil policy were significant factors in the proxy wars of the cold war prior to the downfall of Soviet Communism in the late 1980s and early 1990. Saudi Arabia helped to finance not just the Afghan Mujahideen but also non-Muslim anti-communists. It also seriously harmed the Soviet Communist cause by stabilizing oil prices "throughout the 1980s, just when the Russians were desperate to sell energy in order to keep up with huge hikes in American military spending." Following King Fahd's stroke in 1995, Abdullah, then Crown Prince, assumed responsibility for foreign policy. A marked change in U.S.-Saudi relations occurred, as Abdullah sought to put distance between his policies and the unpopular pro-Western policies of King Fahd. Abdullah took a more independent line from the US and concentrated on improving regional relations, particularly with Iran. Several long-standing border disputes were resolved, including significantly reshaping the Saudi border with Yemen. The new approach resulted in increasingly strained relations with the US. Despite this, the U.S. and Saudi Arabia remained close. In 1998 Abdullah paid a state visit to Washington and met with U.S. President Bill Clinton. In 2003 Abdullah's new policy was reflected in the Saudi government's refusal to support or to participate in the U.S.-led invasion of Iraq.