The U.S. policy of instigating terrorism against any nation which posed the threat of a good example might have something to do with it as well.
These days it seems to be a mixture of coups, terrorism, background fuckery, and outright military invasion of anyone who doesn't serve our interests, particularly regarding our currency. Let's look at a couple examples of that last point.
1. Iraq.
http://archives.cnn.com/2000/WORLD/meast/10/30/iraq.un.euro.reut/ Just three years after switching their oil money to the Euro, we accidentally their whole country and
guess what?
2. Libya.
https://www.youtube.com/watch?v=GuqZfaj34nc The late Muammar Gaddafi had a functional and fully-supported plan to create a new currency throughout much of the Middle-East and Africa known as the gold dinar. The currency would be entirely backed by and made of gold and all interested countries (which involved most muslim and African nations nearby) were fully supportive of the gold dinar and agreed to only sell resources such as oil under the dinar, effectively making the dollar useless.
Suddenly, there were massive civil protests, swift military responses from Western nations, and Gaddafi mysteriously died after being captured. It should be noted that he was in the closing stages of completing the deal with supporting nations and launching the currency when the U.S. and E.U. intervened militarily.
3. Iran and Syria.
http://rt.com/news/iran-gold-currencies-oil-453/ Early last year, Iran announced that it would be willing to accept payments for oil in both gold as well as the national currencies of those importing the oil. Iran had historically accepted payments from other currencies but the gold standard was a new twist. Over the last decade, the United States had been building their case against Iran, pointing to various supposed violations of international nuclear technology regulations. Despite the complete lack of evidence, the U.S. went on to claim that Iran was building nuclear weapons. (Remember the WMDs ten years ago?)
Syria, Iran's closest ally, is now in the midst of a civil war with the U.S. supplying the rebels with war materiél. Recently the United States and Israel accused the Assad regime of using Sarin gas, a deadly chemical weapon. (Is anyone seeing a pattern here?) The United Nations conducted its own research and concluded that the American and Israeli accusations were entirely false and that it was the rebels that had used Sarin. The American backing of rebels in Syria can only be considered a direct provocation to Iran, which has responded by announcing plans to send 4,000 troops to Syria in accordance with their mutual defense agreement.
Furthermore, last year Russia said
this. Russia also recently stated that it would not allow a U.S.-lead institution of a no-fly zone over Syria.
This entire thing is a clusterfuck of global proportions just waiting to happen.
...Oh, and the only things the American dollar are supported by these days are oil, U.S. military might, and blind faith. At the moment those selling the oil are considering a switch to alternate currencies if not already having done so which would destroy the artificial demand for the dollar, the military is tied up, and the faith is slowly withering away.
What happens when the oil runs out as it inevitably will due to international pressure? We can't print more money, we've already done that and made the dollar even flimsier.
What can we do to keep it afloat, you may ask?
Maintain the dollar's dominance over oil at
any cost. Without a constant supply of oil being sold in U.S. Dollars, there would be literally nothing giving it value, thus causing the American economy to collapse entirely.