National Security

National security policy encompasses the size and capabilities of the U.S. military, intelligence gathering, counterterrorism, nuclear weapons, cybersecurity, and the alliances and partnerships that extend American power globally. The United States spends approximately $900 billion annually on defense — more than the next 10 countries combined — and maintains military personnel in more than 70 countries. The post-Cold War era of relative U.S. primacy is giving way to a more contested multipolar environment, with China rapidly expanding its military capabilities and Russia's invasion of Ukraine remaking European security. Major national security debates include: the size of the defense budget and what weapons systems to prioritize; support for NATO and other alliances; whether and how to defend Taiwan; the right balance between military and diplomatic tools; and how to handle the growing threat of cyberattacks against critical infrastructure. Intelligence agencies — the CIA, NSA, DIA, and 16 others — operate with significant secrecy and congressional oversight that is sometimes criticized as insufficient. Nuclear weapons remain a cornerstone of deterrence: the U.S. maintains approximately 5,500 warheads and is undertaking a comprehensive nuclear arsenal modernization estimated to cost $1.7 trillion over three decades.