In the past, attempts by the Middle East to damage the economies of the Western nations have met with high levels of success, as the Western nations have been extremely reliant on oil prices. The most devastating was the first one back in 1973, which began the spiral in oil prices that continues today and will continue to climb in the future.
However, the effects of these embargos are self-defeating. Each time, the citizens of the Western nations become more aware of their own vulnerability to fluctuating oil prices, and seek to remedy this problem through the introduction of new oil rigs off the Gulf of Mexico and in Alaska, connections with other nations such as Venezuela, and seeking of alternate fuel. These activities are rapidly displacing the original supremacy of Middle East oil. The time will soon come for another showdown.
Recently a spite of tension in the Middle East--as can be seen in the War of Iraq, the War of Afghanistan, and the War of Lebanon, as well as questions of nuclear proliferation in Iran--are setting the stage for conditions ripe for another embargo. Traditionally, the embargo had always been a political tool used by the Middle Eastern countries to bring the Westnern nations to their heels. However, due to considerable use of their oil reserves, the Middle East provides less and less of the Western nations' oil consumption every year.
A War with Iran is likely. Should it occur--and even should it not occur--another oil embargo is very likely. Such an event would raise oil prices even more, forcing the governments of the Western nations to take the next step toward greater economical independence from the Middle East.
By 2010, with the passing of Hubbert's Peak in the Middle East, the influence of the embargo will decrease. After a year or so, the Middle Eastern rulers will realize that their tool is now out of date, relinquish the embargo, and be forced to draw even more closely together politically to form an entity capable of challenging the world powers (at this point, the United States and the European Union). This would also mark the end of the Organization of Petroleum Exporting Countries (OPEC), and the end of the use of the oil embargo.