Here's a reminder that governments, in addition to the U.S., have really pushed the limits of stimulus.

Developed nations (The OECD) collectively have slashed their interest rates pretty close to zero as shown in the chart below, on the left. They've also let loose the spigot of government-provided liquidity as show on the right-hand side, below.

They've exhausted the majority of their recession-fighting ammo.

Goldman:

Policy options limited if more stimulus is needed. Policy is much easier than it was in 2008/2009, inflation constraints are smaller and we have not seen a meaningful tightening cycle in most places. But the flipside is that the options for fresh stimulus if the cycle slows again are severely constrained. Fiscal policy is already being used to its limits in many places and conventional monetary policy is already fully employed in much of the G10, and so only unconventional measures (QE) are left in the event of a renewed downturn. This is why many policymakers have been so reticent to withdraw stimulus quickly, but it means that a renewed slowing in growth, either as a consequence of more pressure for fiscal adjustment or otherwise, could be much more dangerous.

(Via Goldman Sachs,Comparing the Sovereign Crisis and the Mortgage Crisis, Jim O'Neill, 9 June 2010)