Generally speaking, I’m part of the crowd that thinks we should be spending more now and tackling the deficit only in the long term. After all, as Paul Krugman and others point 
out endlessly, the “bond vigilantes” are nowhere to be seen. Interest rates are at historic lows and investors — as measured by their real-world actions — seem to have no concerns at all about America’s ability to grow and service its debt.
However, there’s one contrary argument that’s long given me pause. Carmen Reinhart and Kenneth Rogoff, who have written the standard reference about the dangers of countries piling on too much debt, make it here:
Several studies of financial crises show that interest rates seldom indicate problems long in advance. In fact, we should probably be particularly concerned today because a growing share of advanced country debt is held by official creditors whose current willingness to forego short-term returns doesn’t guarantee there will be a captive audience for debt in perpetuity.
Those who would point to low servicing costs should remember that market interest rates can change like the weather. Debt levels, by contrast, can’t be brought down quickly. Even though politicians everywhere like to argue that their country will expand its way out of debt, our historical research suggests that growth alone is rarely enough to achieve that with the debt levels we are experiencing today.
Interest rates are low today. Consumer debt overhang continues to dampen demand and generate massive unemployment. Because of this, government borrowing now not only makes sense because it’s cheap, it makes sense because it will put people back to work and help get the economy back to its long-term growth trend. Especially given the fragility of the world economy — including but not limited to the property bubble in China, the unsustainable flow of hot money into developing countries, and the crisis of the PIIGS in Europe — this is about the worst possible time to take any chances with economic recovery in America.
And yet. Still. Reinhart and Rogoff have a point: investors can get nervous and start fleeing with virtually no notice. One month they’re fat and happy, the next they’re running for the doors. Although we should be spending more now to get the economy back on track, this is why a long-term deficit deal with teeth is something that both liberals and conservatives ought to be willing to compromise to achieve.
