America is on a dangerous budget path. Current spending and debt are dangerously high, and future spending and debt are on track to rise even higher in large part due to increasing entitlement spending. Academic research shows that advanced economies like the United States are at risk of significant and prolonged reductions in economic growth when public debt reaches levels of 90 percent of GDP. High public debt threatens to drive interest rates up, To crowd out private investment, and to raise price inflation. The implications would be severe and pronounced for all Americans, but most especially for the poor, the elderly, and the middle class. U.S. policymakers should learn from Greece and Japan and avoid a fiscal crisis and economic stagnation brought about by public debt overhang.