I. Glenn Cohen is an Assistant Professor and Co-Director, Petrie-Flom Center for Health Law Policy, Biotechnology, and Bioethics, both at Harvard Law School. Stephen Morrissey, the interviewer, is the Managing Editor of the Journal. I.G. Cohen and J.F. Blumstein. The Constitutionality of the ACA's Medicaid-Expansion Mandate. N Engl J Med 2012;