To preserve the option to borrow for extraordinary circumstances, a government must control its debt during more ordinary times. Federal borrowing has grown for generations, aside from a short time at the turn of the century when everything went right. The federal debt burden is reaching its highest level ever and is projected to grow indefinitely. Annual borrowing is growing and adds to the debt at an increasing pace. A debt growing faster than the economy is unsustainable, and the official projections may be optimistic. Fortunately, Congress does not need to pay down the debt. Getting to full balance would rapidly expand fiscal space as the economy grows, but even reaching primary balance—excluding the cost of interest—would be enough to keep the debt burden from exploding. Already, rapidly increasing interest on the debt crowds out other federal priorities and polarizes American politics. A growing debt burden increasingly drives up interest rates and crowds out economic growth by absorbing capital that otherwise could have supported investments that increase prosperity and opportunity. Like Japan, America risks a lost generation of growth but with far greater security dangers.