Abstract: The traditional view of large deficits and debt is that they are harmful, save in recession/early recovery, for tax smoothing or to fund productive public investment, as they crowd out private investment and lower future income, and taken to extremes, can cause inflation, even a financial crisis. Blanchard (2019) concludes they may have no fiscal cost and increase welfare. I present evidence of a debt problem, policies necessary to contain it, effects on recovery, interest rates, and long-run growth. There are several serious issues with Blanchard's reading of key data and modeling assumptions, the changing of which would reverse his conclusions.