The return of a Democratic administration to the White House, coupled with coronavirus disease 2019 (COVID-19) pandemic-induced contractions of job-based insurance, may reignite debate over public coverage expansion and its costs. Decades of research demonstrate that uninsured people and people with copays and deductibles use less care than people with first-dollar coverage. Hence, most economic analyses of Medicare for All proposals and other coverage expansions project increased utilization and associated costs. We review the utilization surges that such analyses have predicted and contrast them with the more modest utilization increments observed after past coverage expansions in the US and other affluent nations. The discrepancy between predicted and observed utilization changes suggests that analysts underestimate the role of supply-side constraints-for example, the finite number of physicians and hospital beds. Our review of the utilization effects of past coverage expansions suggests that a first-dollar universal coverage expansion would increase ambulatory visits by 7-10 percent and hospital use by 0-3 percent. Modest administrative savings could offset the costs of such increases.