Painful sanctions on Iran have demonstrated the long reach of the U.S. Treasury, forcing much of the globe to fall in line and cut oil imports from Iran despite widespread disagreement over the policy. Yet, we are only in the first few chapters of what may ultimately be a long story that ends with the erosion of the power of the U.S. dollar. The role of the greenback in the international financial system is the reason why the U.S. can prevent much of the world from buying oil from Iran. Oil is traded in dollars, and so much of international commerce is based in dollars. In fact, as much as 88 percent of all foreign exchange trades involve the greenback. Moreover, multinational companies inevitably have some commercial ties to the U.S., so when faced with the choice of business with Iran or losing access to the U.S. financial system […]