This paper was prepared for a conference on “The Forces Shaping America’s Fiscal Future” in June 2026. The conference was organized by the Marriner S. Eccles Institute for Economics and Quantitative Analysis at the University of Utah, the Urban-Brookings Tax Policy Center, and the Hutchins Center on Fiscal and Monetary Policy at the Brookings Institution. We are grateful for valuable comments by participants in the conference. The views expressed herein are those of the authors and do not necessarily reflect the views of the National Bureau of Economic Research.