The whole tone of current discussion about deficits is one of urgency: deficits must be brought down now now now or crisis looms. Where is this coming from? Not from the arithmetic.
The way the story is often told, deficits mean higher debt, which means higher interest payments, which can mean a spiral into bankruptcy. And qualitatively that’s not wrong. If you put numbers to it, however, for countries that are not facing huge risk premia, the spiral is very, very slow.
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Still, Serious People tell us that investors will turn on us unless we slash the deficit immediately — and they know this because, well, um …
As I’ve often written, we’re in a strange state now where people who actually take textbook economics and simple arithmetic seriously are seen as dangerously radical and irresponsible, while people who believe in invisible bond vigilantes and confidence fairies, who claim to know what the market will want even though there’s no sign of that desire in current asset prices, are viewed as Very Serious.
http://krugman.blogs.nytimes.com/2011/05/24/debt-arithmetic-wonkish/