Five years and two near-death experiences later, the Patient Protection and Affordable Care Act of 2010 (ACA) has restructured the delivery of American health care. It has provided coverage to millions of Americans who previously lacked it, outlawed discrimination in the insurance marketplace, and armed patients with consumer-based tools to streamline their care. The ACA has had a positive impact throughout the country. But it can only go so far.

Separate from providing access, the most daunting challenge facing American health care, and Medicare in particular, is how to control expenditures and utilization in an era of unprecedented enrollment growth. Past efforts to control expenditure and utilization have failed, and starkly conflict with the dominant paradigm in American health care that sanctifies the autonomy and nearly unlimited discretion of the American health care provider. This paradigm often views attempts that seek cost-effectiveness as heavy- handed government intervention. But as Medicare's enrollment is likely to swell from 52 million today to nearly 90 million by 2040, the costs and utilization problem will not abate with age. While the ACA may help reduce unnecessary and unwanted care and expand coverage, it cannot fully address the overtreatment problem due to a confluence of factors—namely, the often-acute emergent situations and incomparable pain patients encounter, the imperfect agency relationship between patients and payers, and the intractable information asymmetry that exists within the enterprise.

This challenge begs for creative legal and policy-based solutions that seek to maintain provider autonomy and patients' freedom of choice, but also construct reasonable incentives and limitations to prod providers and Medicare beneficiaries into choosing more cost-effective treatments. It is made all the more difficult by Medicare's reimbursement structure, a regime that still largely rewards and incentivizes excess. Recognizing that tension, this piece nods to previous scholarship that has suggested importing fiduciary principles into the provider-patient relationship, but builds on it by arguing for the inculcation of fiduciary principles into the largely unrecognized payer-provider relationship. Requiring the provider to owe a duty of loyalty to the payers in the Medicare enterprise—American taxpayers—would introduce pressures on providers to limit excessive and expensive health care by opening the door for Medicare to seek judicial remedies in cases of wrongdoing. This new duty would further nuance the provider's loyalties and also reflect other professionals' multilayered duties of loyalty. Finally, this move would not increase regulations governing providers, nor rob them of their dear autonomy, but would limit unreasonable health care costs and utilization where possible—something that, heretofore, Medicare has failed to do.