Since late 2012, six of the 104 nuclear reactors in the United States have retired. An additional 13 reactor retirements by 2025 have been announced. These early retirements impact the United States’ ability to reduce greenhouse gas emissions and meet its near- and long-term climate goals. A recent Carnegie Mellon University study found that, without a significant recommitment to nuclear power and change to the policy environment, the United States will continue to shutter nuclear power plants, a critical wedge of reliable and zero-emission electricity, over the next few decades. Policy actions by a few states have averted some planned reactor closures. This brief first reviews lessons learned from these state actions. Then it explores electricity market options and federal programs that could adequately reward nuclear power’s environmental benefits. Preserving the existing U.S. nuclear reactor fleet for as long as practical is a critical element in the transition to a low-carbon future.