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.