While serving in Congress, he kept a campaign promise by returning a congressional pay raise he opposed by writing a check each month to the U.S. Treasury. Coppersmith also gained national attention with his leadership of the effort to eliminate the Advanced Liquid Metal Reactor program, an effort that united a coalition of budget-cutters, environmentalists, and foreign policy experts concerned about plutonium. Also, through his efforts, the U.S. Department of Labor and Department of Education talked with each other to end an interpretation of labor laws that kept parents in some Arizona schools from participating in their children's classrooms.