U.S. federal debt faces pressure. One-quarter of the national debt needs to be refinanced within a year. It may not sound like a big number, but the key is timing—each time such rollover peaks occur, interest rates are forced down to zero. Historical patterns are clear. The problem is that now things are different. Current interest rates remain high and have not fallen back. This is why the market keeps dismissing the narrative of "long-term high interest rates." No matter how smart policymakers are, they can't outsmart mathematics. The pressure of debt, the cost of rollovers, and the reality of interest rates—ultimately—will be reflected in the curve.