Health care spending has grown significantly in the US, and is a major cause of rising federal deficits. Official projections find that low economic growth and aging of the population will lead to a modest continuation of this situation, but they miss that labor shortages have a particular impact on inefficient sectors, raising the cost of health care. We develop a unified macroeconomic model to address this shortcoming, with key variables—particularly in the health care sector and interest rates—endogenously determined. We find that the current fiscal trajectory of the US is unsustainable, with future deficits and debt well beyond both historical norms and official projections. Policy steps, focusing on reducing health care spending, increasing capital, and fiscal retrenchment, can lead to sustainable fiscal conditions and raise living standards that will otherwise fall.