The federal government’s total debt is approaching $18 trillion. Its operating deficit was more than $1 trillion in each of the years 2009–12 and $680 billion in 2013. These numbers are too immense and unfamiliar to be useful. (A trillion is not yet even a standard measure — it means a thousand times a billion in the United States and a million times a billion in much of Europe.) Better to convert them to portions of the economy and government, so that the current debt is 103 percent of U.S. gross domestic product and the 2013 deficit was 4 percent of GDP and 20 percent of federal spending. These ratios put the dollar figures in perspective. The GDP ratio shows the burden of the debt (a larger economy can afford to borrow more, just as a higher-income family can afford a larger home mortgage), and the spending ratio shows how much of our government we are declining to pay for with our taxes. And they facilitate comparisons over time (effectively adjusting for inflation) and across nations with larger and smaller economies. But ratios are still just numbers: They need interpretation to tell us what they mean for our personal circumstances and those of our government.
We are not getting much help from public officials and policy experts, whose interpretations tend to be abstract and amorphous. The consensus formulation, embraced by President Obama, Speaker of the House Boehner, and the Congressional Budget Office, among many others, is that our current debt and deficits are “unsustainable.” This suggests that they are tolerable for the time being but will need to be reduced by some degree sometime in the future. Such a judgment has the advantage of sounding responsible and admonitory while suiting the short time horizons of democratic politicians and their preoccupation with immediate electoral exigencies.