For starters, we need to be aware that we don’t need a balanced budget to have a stable fiscal situation; all we need is for debt to grow no faster than GDP. At the beginning of fiscal 2012, federal debt in the hands of the public was $10 trillion. Meanwhile, most estimates of long-run growth and inflation put them at a bit more than 2 and 2 respectively; so we can reasonably say that nominal GDP growth can be expected to be more than 4 percent per year. If debt grew at 4 percent, it would grow by $400 billion. So the deficit should be scaled down by that much.

That still leaves $700 billion. Where’s that coming from?

OK, revenues were $2.45 trillion, which was 15.7 percent of GDP, at $15.5 trillion. The CBO estimates, however, that potential GDP — what the economy would have produced at full employment — was $16.5 trillion over the same period. And if the economy had been at more or less full employment, we wouldn’t just have collected taxes on the additional income; historically, the tax share of GDP varies strongly with the business cycle. If the economy had been at potential and revenue had been a historically normal 18 percent of GDP, revenue would have been more than $500 billion more than it was; even if revenue had been only 17.5 percent, it would have been almost $450 billion more than it was.

Meanwhile, on the spending side, a large part of the rise in spending came from “income security” payments — in this case, basically unemployment insurance and food stamps — which surged due to high unemployment, but are already coming down. Here’s what happened:



...

Put these together: $400 billion that doesn’t increase the debt-GDP ratio; $450 billion or so in slump-related revenue loss; $150 billion or more in slump-related expenses; and guess what: the ONE TRILLION DOLLARS is basically just a depressed-economy story, having nothing to do with any fundamental mismatch between what we want and what we’re willing to pay.