The Fed has always wanted to launch a third round of quantitative and loose monetary policy, also known as QE3, to boost the recovery of the US economy  If the Fed launches QE3, the global supply of dollars will increase sharply again, and countries will have to buy dollar assets in order to maintain exchange rate stability  If countries buy dollar assets, it will increase inflationary pressure in their own countries  If you don't want to import inflation, countries have to let their currencies appreciate
If the local currency appreciates, it will depress domestic exports and lead to an economic downturn
Other countries are either facing imported inflationary pressures or are in danger of economic decline.