1944 Bretton Woods Conference firmly established the U.S. Dollar as the global reserve currency.
1971, President Nixon officially ended the international convertibility from U.S. dollars into gold, thereby bringing an official end to the Bretton Woods arrangement.
Two years later, in an effort to maintain global demand for U.S. dollars, another system was created called the petrodollar system. In 1973, a deal was struck between Saudi Arabia and the United States in which every barrel of oil purchased from the Saudis would be denominated in U.S. dollars. Under this new arrangement, any country that sought to purchase oil from Saudi Arabia would be required to first exchange their own national currency for U.S. dollars. In exchange for Saudi Arabia's willingness to denominate their oil sales exclusively in U.S. dollars, the United States offered weapons and protection of their oil fields from neighboring nations, including Israel.
By 1975, all of the OPEC nations had agreed to price their own oil supplies exclusively in U.S. dollars in exchange for weapons and military protection.
Before the 2003 invasion, Iraq's domestic oil industry was fully nationalized and closed to Western oil companies. A decade of war later, it is largely privatized and utterly dominated by foreign firms.
As the U.S. dollar continued to lose purchasing power, several oil-producing countries began to question the wisdom of accepting increasingly worthless paper currency for their oil supplies. Today, several countries have attempted to move away, or already have moved away, from the petrodollar system. Examples include Iran, Syria, Venezuela, and North Korea...additionally, other nations are choosing to use their own currencies for oil like China, Russia, India, among others.
What is going on in the Middle East? Research the Petrodollar System. Any country that doesn't play ball with the US is either invaded, demonized, bullied or beaten into submission.