Almost every country, including the United States, is on a system of fiat money, which the glossary defines as "money that is intrinsically useless; is used only as a medium of exchange". We saw in the article "Why Does Money Have Value" that the value of money is set by the supply and demand for money and the supply and demand for other goods and services in the economy. The prices for those goods and services, including gold and silver, are allowed to fluctuate based on market forces
http://economics.about.com/cs/money/a/gold_standard_2.htmThe stability the gold standard cause in the foreign exchange market is often cited as one of the benefits of the system.
The stability caused by the gold standard is also the biggest drawback in having one. Exchange rates are not allowed to respond to changing circumstances in countries. A gold standard severely limits the stabilization policies the Federal Reserve can use. Because of these factors, countries with gold standards tend to have severe economic shocks. Economist Michael D. Bordo explains:
"Because economies under the gold standard were so vulnerable to real and monetary shocks, prices were highly unstable in the short run. A measure of short-term price instability is the coefficient of variation, which is the ratio of the standard deviation of annual percentage changes in the price level to the average annual percentage change. The higher the coefficient of variation, the greater the short-term instability. For the United States between 1879 and 1913, the coefficient was 17.0, which is quite high. Between 1946 and 1990 it was only 0.8.
Moreover, because the gold standard gives government very little discretion to use monetary policy, economies on the gold standard are less able to avoid or offset either monetary or real shocks. Real output, therefore, is more variable under the gold standard. The coefficient of variation for real output was 3.5 between 1879 and 1913, and only 1.5 between 1946 and 1990. Not coincidentally, since the government could not have discretion over monetary policy, unemployment was higher during the gold standard. It averaged 6.8 percent in the United States between 1879 and 1913 versus 5.6 percent between 1946 and 1990."
So it would appear that the major benefit to the gold standard is that it can prevent long-term inflation in a country. However, as Brad DeLong points out, "if you do not trust a central bank to keep inflation low, why should you trust it to remain on the gold standard for generations?" It does not look like the gold standard will make a return to the United States anytime in the foreseeable future.
Interesting read.