From their downgrade report:
Key macroeconomic assumptions in the base case scenario include trend real GDP growth of 3 percent and consumer price inflation near 2 percent annually over the decade. ... our downside case scenario assumes relatively modest real trend GDP growth of 2.5 percent and inflation of near 1.5 percent annually going forward.
Real GDP in the first decade of the 21st century was a pathetic, anemic 1.67 percent.
If that continues (we're at 1.3 percent right now), the gap between spending and revenues will continue to widen, increasing the size of annual deficits and adding to the total debt.
