Remember: there are two primary mechanisms which control international monetary trade in the Dollar:
(1) Monetary movement determined by international trade. Some guy buys an American product in Europe; he exchanges Euros into Dollars, and that trade along with millions of others are traded on the international exchange in order to allow him to buy his product.
(2) Monetary investment separate from international trade. Countries and large corporations will hold currencies of various countries for investment purposes--for example, France may hold U.S. dollars in order to hedge against inflation, or to hedge against risks against currency movement. And their holdings may either be pure dollars or in treasury bills.
Those who look at the declining dollar today and are squawking about how this somehow proves the failure of President Obama's foreign policy or the failure of President Bush's policies (that somehow Obama inherited) are demonstrating their lack of a long-term memory. Compared to the Japanese Yen, the Dollar has been declining since 1971 when the Yen was fixed against the Dollar at ¥360 to $1 by the original Bretton Woods accord. When the Yen and Dollar were allowed to float, in 1973 (after the exchange rate was adjusted in 1972 to ¥308 to $1), the dollar has been in steady decline as both the Japanese economy restructured itself into a modern (post-World War II) economy, and as countries since the 1990's have moved away from the U.S. Dollar as the world's reserve currency.
Even if you discount the rapid decline of the dollar compared to the yen from 1973 to 1988, there still is a steady decline in the dollar relative to the yen as long term monetary investors shift their portfolios away from a post-Bretton Woods II world and to a world where a basket of currencies make far more sense than holding strictly in dollars.
Yes, it is true that perhaps some of the decline in the dollar is due to uncertainty in the Obama Administration's treatment of the dollar. People hold dollars to hedge against risk--but when the current Democratic-controlled government acts erratically, that uncertainty increases risk, and that risk makes dollars look less appealing for risk management.
But for the most part the decline in the dollar is generational--a further readjustment that has been taking place since the European reconstruction after World War II.