If we don’t start cutting, we will hit the debt wall by July, 2012. There is a limited amount of money that the world’s sovereign governments can borrow in any single given year without pressuring interest rates to rise above the point of affordability. This limit is approximately 9% of the world’s gross domestic product (GDP). Read here: debtwall.org
This is why we had QE1 and QE2 and why we are shoring up the Euro.