Credit Rating Agencies are like snails.
They were slow to recognise their rubber stamping of subprime debt was too punchy and slowly downgraded junk way after it was junk. Look at Greece. It has been junk since it joined the EU.
Take the USA. It has way too much debt but because it has the world's currency it can print its way out of trouble. Greece is bust but thankfully the Greeks can rely on the EU, ECB and IMF to help fund its excesses. The USA has nobody to help bail it out. The Middle East so badly burned by Lehman has a long memory. The Chinese whose contract of "we will buy your debt if you keep off our hugely undervalued currency" is starting to look wobbly.
Once commodities are no longer priced in USD, America will go the way of Greece. This sounds dramatic but it will. As a country it can be completely self sufficient and that is its last hope. Why doesn't Obama bang tarriffs on foreign imports? He could but needs these foreigners to flood the USA will cheap goods it cannot produce. An aging population and lazy young workers. China is cheap because it has cheap labour. Its raw material costs are high because of its low currency and that is why it is buying up Africa and Australia.
Moodys is now looking at putting the USA's AAA rating on watch. And then it will be downgraded. Its yeilds will go up and Bernanke will have to print even more. Not very pleasant.
US unemployment moves towards 10% (telegraph)
Run on Greek banks inevitable (afp)
IMF is cool with Greece. Says Greece (reuters)
America to double dip.