The current payment system for Medicare+Choice (M+C) plans is based on prices calculated from administrative records. This system has been criticized as arbitrary, inefficient, and unfair. Most Medicare reform proposals would replace the current payment system with some form of competitive pricing. However, efforts over the past five years to demonstrate competitive pricing for M+C plans have been blocked repeatedly by Congress, even when the demonstrations were directly responsive to a congressional mandate. In the absence of political support, a demonstration of competitive pricing may be infeasible, and Congress could be forced to take the risky step of implementing broad Medicare reforms with very little information about their effects.