This is why I am so steadfastly unconvinced by people who point to our low interest rates as evidence that the market thinks it's safe to borrow. When higher real interest rates come, they will not be a timely signal of problems ahead unless we change course--they will be the problem. The term structure of US debt is pretty short, with an average maturity of under five years, and Republicans are complaining that we've been issuing too much short-term debt lately. If interest rates climb significantly, our interest expense will start putting a lot of pressure on an already weak fiscal position. Arguing that we're fine because interest rates are low is like arguing that the Titanic must be safe because it hasn't run into an iceberg yet.