The United States Coast Guard (USCG) is the maritime security, search and rescue, and law enforcement service branch of the United States Armed Forces and one of the country's eight uniformed services. The service is a maritime, military, multi-mission service unique among the United States military branches for having a maritime law enforcement mission with jurisdiction in both domestic and international waters and a federal regulatory agency mission as part of its duties. It is the largest and most powerful coast guard in the world, rivaling the capabilities and size of most navies.

The U.S. Coast Guard is a humanitarian and security service. It protects the United States' borders and economic and security interests abroad; and defends its sovereignty by safeguarding sea lines of communication and commerce across vast territorial waters spanning 95,000 miles of coastline and its Exclusive Economic Zone. With national and economic security depending upon open global trade and a rules-based international order, and with ever-expanding risk imposed by transnational threats through the maritime and cyber domains, the U.S. Coast Guard is at any given time deployed to and operating on all seven continents and in cyberspace to save lives; enforce laws; ensure safe and secure commerce; and protect the environment. Like its United States Navy sibling, the U.S. Coast Guard maintains a global presence with permanently-assigned personnel throughout the world and forces routinely deploying to both littoral and blue-water regions. The rise of great power competition and adversarial challenges to rules-based international order through inter-state aggression, economic coercion, and maritime hybrid warfare has cultivated numerous conflict hotspots around the world. The U.S. Coast Guard's adaptive, multi-mission "white hull" fleet is leveraged as a force of both diplomatic soft power and humanitarian and security assistance over the more overtly confrontational nature of "gray hulled" warships. As a humanitarian service, it saves tens of thousands of lives a year at sea and in U.S. waters, and provides emergency response and disaster management for a wide range of man-made and natural catastrophic incidents in the U.S. and throughout the world.The U.S. Coast Guard operates under the U.S. Department of Homeland Security during peacetime. During times of war, it can be transferred in whole or in part to the U.S. Department of the Navy under the Department of Defense by order of the U.S. President or by act of Congress. Prior to its transfer to Homeland Security, it operated under the Department of Transportation from 1967 to 2003 and the Department of the Treasury from its inception until 1967. A congressional authority transfer to the Navy has only happened once: in 1917, during World War I. By the time the U.S. entered World War II in December 1941, the U.S. Coast Guard had already been transferred to the Navy by President Franklin Roosevelt.Created by Congress as the Revenue-Marine on 4 August 1790 at the request of Alexander Hamilton, it is the oldest continuously operating naval service of the United States. As Secretary of the Treasury, Hamilton headed the Revenue-Marine, whose original purpose was collecting customs duties at U.S. seaports. By the 1860s, the service was known as the U.S. Revenue Cutter Service and the term Revenue-Marine gradually fell into disuse.The modern U.S. Coast Guard was formed by a merger of the U.S. Revenue Cutter Service and the U.S. Life-Saving Service on 28 January 1915, under the U.S. Department of the Treasury. In 1939, the U.S. Lighthouse Service was also merged into the U.S. Coast Guard. As one of the country's six armed services, the U.S. Coast Guard has deployed to support and fight every major U.S. war since 1790, from the Quasi-War with France to the Global War on Terrorism.As of December 2021, the U.S. Coast Guard's authorized force strength is 44,500 active duty personnel and 7,000 reservists . The service's force strength also includes 8,577 full-time civilian federal employees and 31,000 uniformed volunteers of the U.S. Coast Guard Auxiliary. The service maintains an extensive fleet of roughly 250 coastal and ocean-going cutters, patrol ships, buoy tenders, tugs, and icebreakers; as well as nearly 2,000 small boats and specialized craft. It also maintains an aviation division consisting of more than 200 helicopters and fixed-wing aircraft. While the U.S. Coast Guard is the second smallest of the U.S. military service branches in terms of membership, the service by itself is the world's 12th largest naval force.

The war on drugs is a global campaign, led by the U.S. federal government, of drug prohibition, military aid, and military intervention, with the aim of reducing the illegal drug trade in the United States. The initiative includes a set of drug policies that are intended to discourage the production, distribution, and consumption of psychoactive drugs that the participating governments and the UN have made illegal. The term was popularized by the media shortly after a press conference given on June 18, 1971, by President Richard Nixon—the day after publication of a special message from President Nixon to the Congress on Drug Abuse Prevention and Control—during which he declared drug abuse "public enemy number one". That message to the Congress included text about devoting more federal resources to the "prevention of new addicts, and the rehabilitation of those who are addicted" but that part did not receive the same public attention as the term "war on drugs". Two years prior to this, Nixon had formally declared a "war on drugs" that would be directed toward eradication, interdiction, and incarceration. In 2015, the Drug Policy Alliance, which advocates for an end to the War on Drugs, estimated that the United States spends $51 billion annually on these initiatives, and in 2021, after 50 years of the drug war, others have estimated that the US has spent a cumulative $1 trillion on it.On May 13, 2009, Gil Kerlikowske—the Director of the Office of National Drug Control Policy (ONDCP)—signaled that the Obama administration did not plan to significantly alter drug enforcement policy, but also that the administration would not use the term "War on Drugs", because Kerlikowske considers the term to be "counter-productive". ONDCP's view is that "drug addiction is a disease that can be successfully prevented and treated... making drugs more available will make it harder to keep our communities healthy and safe".In June 2011, the Global Commission on Drug Policy released a critical report on the War on Drugs, declaring: "The global war on drugs has failed, with devastating consequences for individuals and societies around the world. Fifty years after the initiation of the UN Single Convention on Narcotic Drugs, and years after President Nixon launched the US government's war on drugs, fundamental reforms in national and global drug control policies are urgently needed." The report was criticized by organizations that oppose a general legalization of drugs.