Here’s a great excerpt from an article in the latest print edition of The Economist, “America’s vulnerable economy”:

The rising importance of the world’s new giants [BRICs] will not only boost growth. It will also shift relative prices, notably those of oil and the dollar. And the consequences of this will be less comfortable for developed countries, especially America.

The oil price has risen mainly because of strong demand in emerging economies, which have accounted for as much as four-fifths of the total increase in oil consumption in the past five years. In past American recessions the oil price usually fell. This time it is likely to hold up. That will not only hurt the finances of Western consumers, but may also make the jobs of their central bankers harder, by combining inflationary pressure with economic slowdown.

The enfeebled dollar—lately in sight of $1.50 to the euro—would be weaker still without enormous purchases by central banks in emerging economies. This support is now waning. China and others are putting a smaller share of increases in reserves into the American currency. And Asian and Middle Eastern countries with currencies linked to the dollar are facing rising inflation, but falling American interest rates make it harder to tighten their own monetary policy. They may have to let their currencies rise against the sickly greenback, meaning they will need to buy fewer dollars. More important, as international investors wake up to the relative weakening of America’s economic power, they will surely question why they hold the bulk of their wealth in dollars. The dollar’s decline already amounts to the biggest default in history, having wiped far more off the value of foreigners’ assets than any emerging market has ever done.

The vigour of emerging economies is good news for the world economy: for its growth, it has much less need of a strong America. The bad news for America is that this, in turn, may mean that the world also has less need of the dollar.