They contend that shielding prediction markets from state regulation violates the traditional coequal role of state and federal governance, undermining the states’ traditional power to protect consumers. The CFTC sued Arizona, Connecticut, and Illinois to assert its authority over prediction markets. And lawmakers have introduced federal legislation seeking to ban sports betting on prediction markets. The answer will determine which regulator has jurisdiction and the future of prediction markets in the United States. They also consider the risks prediction markets pose to information integrity and public trust as they expand into contested political and social subjects, proposing reforms for regulating event contracts.