With conflicting rulings about the constitutionality of the individual mandate in the Affordable Care Act (ACA), we are left to wonder: what would the ACA look like if its individual mandate was dropped? A new report using the Urban Institute’s Health Insurance Policy Simulation Model (HIPSM) shows that the number of uninsured would be cut by more than half with the mandate, but by only about 20 percent without the mandate. Uncompensated care would decline by $42.4 billion under the ACA, but only by $14.7 billion under reform without a mandate because of the large number of people remaining uninsured.