The United States has played a prominent role in the Middle East since the end of World War II, due in no small part to the large amounts of oil in the region. The U.S. under Harry Truman recognized Israel shortly after its founding in 1948, and the new country quickly became a large-scale consumer of U.S. military aid. The United States became heavily involved in the region with the outbreak of the Suez crisis in 1956. After restraining Great Britain and France, President Dwight Eisenhower articulated what became known as the Eisenhower Doctrine, in which the United States announced its intention to resist any attempts at spreading communism in the Middle East. Acting on this principle, the American government supported anti-communist leaders throughout the region, which engendered a great deal of anti-American sentiment in the Muslim world. Eisenhower and several other presidents, including Ronald Reagan, sent Marines to Lebanon in particular to protect American interests there.
Another cornerstone in American foreign policy was the attempt to bring an end to the highly strained relationship between the Israelis and the rest of the Arab world. In 1978, a huge step toward this goal was accomplished with the Camp David Accords, a peace agreement between Israel and Egypt that was brokered by President Jimmy Carter. Israel remained unpopular in the Arab world, however, due to the continued friction with their Palestinian neighbors, and U.S. support for the Israeli state remains a key point of anger with many in the Arab world. In 1991, the United States and a coalition of nations invaded Iraq to secure Iraqi withdrawal from Kuwait. This move, because it occasioned US forces being stationed in Saudi Arabia, became a major source of anti-Americanism.
Another problem was the continued support by American presidents for corrupt Arab leaders, solely because they were against radical Islamists. After the attacks by Al-Qaeda, the American presence in the Middle East was increased, and the overthrow of Saddam Hussein, and the devastating civil war that followed in Iraq, ensured that the United States will maintain a major presence in the region for the foreseeable future.