 of nuclear weapons through renewed arms control and nonproliferation leadership. We will continue to seek pragmatic engagement with competitors about strategic stability and risk reduction. Our approach will emphasize measures that head off costly arms races, reduce the likelihood of miscalculation, and complement U.S. and allied deterrence strategies. We will lead bilateral and multilateral arms control efforts and strengthen existing regimes, frameworks, and institutions, including the Nuclear Non-Proliferation Treaty, Comprehensive Test Ban Treaty Organization, International Atomic Energy Agency, and other United Nations bodies, to extend the more than seven-decade record of nuclear non-use. We will support the Organization for the Prohibition of Chemical Weapons and the Biological Weapons Convention and reinforce norms against the possession and use of chemical and biological weapons. We will continue to lead the world in coordinated efforts to lock down nuclear and radiological materials and prevent terrorist acquisition. And we will ensure multilateral export control regimes are equipped to address destabilizing emerging technologies and to align export policies in likeminded states toward countries of concern. Terrorism Today’s terrorist threat is more ideologically diverse and geographically diffuse than that of two decades ago. Al-Qa‘ida, ISIS, and associated forces have expanded from Afghanistan and the Middle East into Africa and Southeast Asia. Syria, Yemen, and Somalia remain terrorist sanctuaries; local affiliates have become entrenched actors in regional conflicts. Many of these groups still intend to carry out or inspire others to attack the United States and our interests abroad, even as years of sustained counterterrorism and law enforcement pressure have constrained their capabilities, and enhanced security measures and information sharing have improved our defenses. Meanwhile, we face sharply increased threats from a range of domestic violent extremists here in the United States. America remains steadfast in protecting our country and our people and facilities overseas from the full spectrum of terrorism threats that we face in the 21st century. As the threat evolves, so too must our counterterrorism approach. To that end, last year, we ended America’s longest war, in Afghanistan, having long ago achieved our objective of delivering justice to Osama Bin Laden and other key leadership of al-Qa’ida. We are confident in our ability to maintain the fight against al-Qa’ida, ISIS, and associated forces from over the horizon, as we demonstrated with the operation to kill Ayman al-Zawahiri. We will ensure Afghanistan never again serves as a safe haven for terrorist attacks on the United States or our allies and we will hold the Taliban accountable for its public commitments on counterterrorism. Around the world, we will increase cooperation and support to trusted partners, shifting from a strategy that is “U.S.-led, partner-enabled” to one that is “partner-led, U.S.-enabled.” That requires building or expanding systems to prevent, detect, and respond to threats as they develop—including by strengthening partners’ law enforcement and judicial systems, improving threat information sharing, enhancing border security, countering terrorist financing, targeting terrorist prevention and extremist disengagement programming, and preventing online and offline terrorist recruitment and mobilization to violence. It also necessitates addressing the root causes of radicalization by leveraging U.S. and partner efforts to support effective governance, promote stabilization and economic development, and resolve ongoing conflicts. 30 NATIONAL SECURITY STRATEGY