Just a little bit of simple debt and deficit arithmetic. Let's adjust the deficit for long run inflation and long run real growth. That cuts the deficit by around $27 billion.
$600 billion debt times 2% inflation equals $12 billion. The Federal government could run a deficit of $12 billion this year and the real (inflation-adjusted) debt would stay the same.
The same debt that would ruin a poor country would be nothing to a rich country. Looking at the debt/GDP ratio seems a more sensible measure of whether a country is increasing or decreasing the difficulty of servicing the debt. Long run growth in real GDP is harder to forecast. I'm going to assume 2.5% real growth. It will be more than that some years and less than that in other years. It all depends on population growth, demographics (percentage of population that is working age), productivity growth, and the business cycle too in the short run. But something like 2.5% seems a reasonable average for the next decades.
$600 billion debt times 2.5% real growth equals $15 billion. If there were no inflation, and 2.5% real GDP growth, the Federal government could run a deficit of $15 billion this year and the debt/GDP ratio would stay the same.
Add 2% inflation plus 2.5% real GDP growth and you get 4.5% nominal GDP growth. The debt can grow at 4.5% per year and the debt/Nominal GDP ratio would stay the same. That means a deficit of $27 billion this year.
Once you adjust for expected inflation and expected real growth, the Federal deficit looks more like a small surplus.
That isn't the end of the debate, of course. Maybe fiscal policy should be tighter, because of the future costs of supporting ageing boomers? Maybe it should be looser, because the recession isn't really quite over (relative to trend)? Maybe interest rates will continue to stay lower than in the past, so interest payments will fall as the long-term debt gets rolled over? Maybe we want to slowly reduce the debt/GDP ratio because of uncertainty? Maybe we want to increase the debt/GDP ratio because interest rates will stay below the growth rate, so Ponzi-finance is sustainable?
But it is a much more sensible place to begin the debate.