The Keynesian Endpoint

What happens now? Economics in an age when fiscal stimulus can't be funded and no longer works.

After Lehman fell, the scope of the financial crisis became so great that only the fiscal and monetary authorities possessed balance sheets large enough to resolve it. But if the U.S. is backing its financial system, who's backing the U.S.? Practically, nations have reached "the Keynesian Endpoint": No more balance sheets are left to support either economic activity or the financial system.