In the 1990s the United States ceased underground nuclear testing, and the U.S. Department of Energy created the science-based Stockpile Stewardship Program to maintain the safety, security, and reliability of the U.S. nuclear deterrent without full-scale testing. With decades of world-leading research on lasers and inertial confinement fusion, Lawrence Livermore National Laboratory (LLNL) was uniquely positioned to meet the challenge of studying the science of nuclear weapons in the absence of underground testing. And when the nation needed a new scientific instrument to ensure continued confidence in our nuclear stockpile, LLNL provided a solution—the National Ignition Facility (NIF), the world’s highest-energy laser system (see NIF and Stockpile Stewardship).