The United States Coast Guard (USCG) is a maritime, multi-mission service unique among the U.S. military branches for having a maritime law enforcement mission and a federal regulatory agency mission as part of its mission set. It operates under the U.S. Department of Homeland Security during peacetime, and can be transferred to the U.S. Department of the Navy by the U.S. President at any time, or by the U.S. Congress during times of war.
On 25 November 2002, the Homeland Security Act was signed into law by U.S. President George W. Bush, designating the Coast Guard to be placed under the U.S. Department of Homeland Security. The transfer of administrative control from the U.S. Department of Transportation to the U.S. Department of Homeland Security was completed the following year, on 1 March 2003.
The U.S. Coast Guard reports directly to the Secretary of Homeland Security. However, under 14 U.S.C. § 3 as amended by section 211 of the Coast Guard and Maritime Transportation Act of 2006, upon the declaration of war and when Congress so directs in the declaration, or when the President directs, the Coast Guard operates under the Department of Defense as a service in the Department of the Navy.
Title 14 USC, section 2 authorizes the Coast Guard to enforce U.S. federal laws. This authority is further defined in 14 U.S.C. § 89, which gives law enforcement powers to all Coast Guard commissioned officers, warrant officers, and petty officers. Unlike the other branches of the United States Armed Forces, which are prevented from acting in a law enforcement capacity by 18 U.S.C. § 1385, the Posse Comitatus Act, and Department of Defense policy, the Coast Guard is exempt from and not subject to the restrictions of the Posse Comitatus Act.
Further law enforcement authority is given by 14 U.S.C. § 143 and 9 U.S.C. § 1401, which empower U.S. Coast Guard active and reserve commissioned officers, warrant officers, and petty officers as federal customs officers. This places them under 19 U.S.C. § 1589a, which grants customs officers general federal law enforcement authority.
The Coast Guard has as a part of Department of Homeland Security roles in maritime homeland security, maritime law enforcement (MLE), marine environmental protection (MEP), the maintenance of river, intracoastal and offshore aids to navigation (ATON).
Homeland security missions:
* Defense readiness
* Maritime law enforcement
* Migrant interdiction
* Ports, waterways and coastal security (PWCS)
* Drug interdiction