The US debt downgrade has started...

From Bloomberg:

“The downgrade reflects our opinion that the fiscal consolidation plan that Congress and the Administration recently agreed to falls short of what, in our view, would be necessary to stabilize the government’s medium-term debt dynamics,” S&P said in a statement late yesterday after markets closed.

From Krugman:

"More than that, everything I’ve heard about S&P’s demands suggests that it’s talking nonsense about the US fiscal situation. The agency has suggested that the downgrade depended on the size of agreed deficit reduction over the next decade, with $4 trillion apparently the magic number. Yet US solvency depends hardly at all on what happens in the near or even medium term: an extra trillion in debt adds only a fraction of a percent of GDP to future interest costs, so a couple of trillion more or less barely signifies in the long term. What matters is the longer-term prospect, which in turn mainly depends on health care costs.

So what was S&P even talking about? Presumably they had some theory that restraint now is an indicator of the future — but there’s no good reason to believe that theory, and for sure S&P has no authority to make that kind of vague political judgment."