Today’s warfighter, leader, and policymaker advance American interests while confronting a strategic environment that is dynamic and increasingly competitive. The 2021 Interim National Security Strategic Guidance depicts the global security landscape as one characterized by new crises and accelerating challenges, many of which find their locus in governments or events far from our shores. Our nation continues to contend with adversarial state actors as well as familiar hazards inspired by terrorism and extremism. Yet we are also witnessing new challenges such as ramifications of climate change, threats engendered by scientific and technological innovation, intensified efforts to aggressively reframe or undermine the international order, and pursuits to expand the availability, reach, and potency of catastrophic weapons.