Petroleum politics have been an increasingly important aspect of diplomacy since the rise of the petroleum industry in the Middle East in the early 20th century. As competition continues for a vital resource, the strategic calculations of major and minor countries alike place prominent emphasis on the pumping, refining, transport, sale and use of petroleum products. Quota agreements The Achnacarry Agreement or "As-Is Agreement" was an early attempt to restrict petroleum production, signed in Scotland on 17 September 1928. The discovery of the East Texas Oil Field in the 1930s led to a boom in production that caused prices to fall, leading the Railroad Commission of Texas to control production. The Commission retained de facto control of the market until the rise of OPEC in the 1970s. The Anglo-American Petroleum Agreement of 1944 tried to extend these restrictions internationally but was opposed by the industry in the United States and so Franklin Roosevelt withdrew from the deal. Venezuela was the first country to move towards the establishment of OPEC by approaching Iran, Gabon, Libya, Kuwait and Saudi Arabia in 1949, but OPEC was not set up until 1960, when the United States forced import quotas on Venezuelan and Persian Gulf oil in order to support the Canadian and Mexican oil industries. OPEC first wielded its power with the 1973 oil embargo against the United States and Western Europe. Oil and international conflict The term "petro-aggression" has been used to describe the tendency of oil-rich states to instigate international conflicts. There are many examples including: Iraq's invasion of Iran and Kuwait; Libya's repeated incursions into Chad in the 1970s and 1980s; Iran's long-standing suspicion of Western powers. Some scholars have also suggested that oil-rich states are frequently the targets of "resource wars." Cullen Hendrix, author of the academic article "Oil Prices and Interstate Conflict", focuses on creating a more sound measurement of and index, building off of Colgan and Weeks indices respectfully. Hendrix findings are such that as the price in oil goes up the more confrontational a petro-state becomes. This may be due to the fact that these countries can now invest more heavily in their military. When people feel secure, they tend to give a higher approval rating to the leader. A petro-state GDP will grow, offering the opportunity for a more diverse industry, which in turn gives more bargaining chips in terms of global negotiations. Peak oil In