The Three Mile Island Unit 2 (TMI-2) accident led to significant changes in the U.S. Nuclear Regulatory Commission (NRC), the nuclear industry, public utility commissions, and Congress. The major changes occurred in the NRC, where the fundamental effect was to change the relationship between industry and the regulator. Prior to TMI-2, this relationship was a comfortable mutual resolution of problems by technical professionals. After TMI-2, the relationship became adversarial, arms-length, and dominated by legalism.