The US economy was relatively isolated from the world for the first 150 years. Post WWII the US economy had to be economically connected to the world in order to sell all the goods that the US produced using the war machinery that had to be maintained after 1945.
Now, because all free market economies are globally connected, currencies not only can but must be devalued to reflect the relative strength of one economy relative to the other.
Given that the strength of a economy is directly related to its borrowing, rate of growth, and unemployment, it is a given that the strength or weakness in one economy in the world will affect the value of its currency relative to others. Since global trade is based on a pretty well-established relationship between global economies today, quick movements in currencies has a very destabilizing effect on all world economies. Thus, Japan's decision to try to stimulate their economy and Italy's weakening economy all have to be matched by actions of other countries or global trade is thrown off balance. Unemployment in Europe cannot occur w/o having a similar level in other countries or the value of other economies relative to Europe will become mismatched. Given that unemployment forces down (or limits the growth of) wage levels but also results in the necessity by democratic governments to implement social programs to limit the pain to the people, it is not realistic to fix one economy as long as others in the same position. Global economics today has resulted in pulling down the strongest economies while at the same time many of the formerly poorest of the poor in the world are better off than they were 30 years ago as their governments export to wealthier economies. Global wealth is being shared more but it is the middle class of Europe and the US that have been most impacted; remember, though, that the concept of middle class is not terribly old in the history of human civilization and it is the US that is recognized as having done the most to develop the middle class.
Les Miserables was a good reminder that people will reach a point when they will overthrow governments in order to protect their own personal interests; being unable to find food for your family is a powerful motivator. However, since most western governments are democratic now, they have little choice but to throw money into social programs in order to stop suffering from going as far as it did right before the French Revolution.
People will act when they reach poverty levels and cannot meet their basic needs; they rarely overthrow and destabilize their country solely to maintain middle class standards of living. The events of Europe today are testing the limits of how far governments can cut and allow the free markets to work with their sometimes painful consequences before people will overthrow their governments.
