Medicare costs are rising faster than projected revenues. Action to close the emerging deficit is inescapable. We propose converting Medicare from a "service reimbursement" system to a "premium support" system. These changes would resemble many that are now reshaping private employer-based insurance. Our reform would encompass not just the "public" Medicare program but also the "real" Medicare, which includes the supplemental plans to which most Medicare beneficiaries have access. Approved plans would have to offer stipulated services. We review numerous technical issues in moving to a new system that cannot be solved quickly and that preclude quick budget savings.