USA and Greece with the same problem?

Looks like the USA economy is in a worst state (relatively speaking) than Greece or Portugal with the US having until the end of the week to come up with immediate reforms to its financial system or face having to default on its huge debts. The crisis could be avoided if the Obama administration proposal to increase taxes on the wealthy was agreed but for that to happen the Republicans would have to agree to the measures and this does not seem to be happening right now. So it will seem that the Greeks are in the same boat with the all mighty USA? None of this makes sense... should the entire world system be changed? Why should the markets decide what democratically elected countries can or cannot do? Who are the markets? A small ruling elite of super rich men...