The United States has land borders with only Canada and Mexico, both of them long. It has maritime boundaries with many countries due to its extensive exclusive economic zone (EEZ). All of its maritime borders with Canada are at least partially disputed, and its territorial claims on three Caribbean islands are disputed.
The de facto boundary between the United States and Russia is defined by the USSR–USA Maritime Boundary Agreement, negotiated with the Soviet Union in 1990,[1] covering the Bering Sea, Bering Strait, and Arctic Ocean. The agreement was never ratified by the Soviet Union before it dissolved, and it has never been ratified by the Russian State Duma. It has been ratified by the United States Senate, respected in practices by both governments, and defended against encroachment by fishing vessels. The boundary line generally follows the line agreed to during the 1867 Alaska Purchase, though this could not be entirely determined because neither country could produce maps agreed to at that time.
New Brunswick-Maine maritime border and islands: While the 1984 Gulf of Maine Case submitted to the International Court of Justice[3] established most of Atlantic maritime boundary between the United States and Canada,[4] the parties agreed to exclude from that case Machias Seal Island and North Rock and nearby portions of the maritime boundary. This created a "grey zone" of overlapping claims near the disputed islands (and has contributed to "grey-zone conflict). Machias Seal Island is occupied by Canada, and the disputed waters are patrolled by both nations. The strength of near-shore maritime claims depend on how the island sovereignty dispute is resolved.
Swains Island has been administered by the United States as part of American Samoa since 1925. New Zealand, of which Tokelau is a dependency, recognized U.S. sovereignty in a 1980 treaty.[5] The uninhabited island was claimed for Tokelau in the constitution that was almost adopted in the 2006 Tokelauan self-determination referendum.
Disputed occupation
The United States administers Guantanamo Bay Naval Base on what both countries agree is the sovereign territory of Cuba under a permanent lease obtained under the Cuban–American Treaty of Relations (1903), while Cuba was under American military occupation after the 1898 Spanish–American War. After the Cuban Revolution in the 1950s, Cuba disputed the validity of this lease and ceased cooperating with the base. The boundary is highly militarized, but the United States has maintained control without active fighting.
The United States Coast Guard actively patrols the nation's extensive maritime borders, acting as a law enforcement agency in peacetime. The United States Armed Forces are generally prohibited from domestic law enforcement (including arresting smugglers and illegal immigrants) under the Posse Comitatus Act, but can be activated to secure the border in an emergency or respond to an attack. State and federal National Guard troops and even active-duty military personnel have been used in support roles at the border, which has been controversial and limited by legal complexities.[6][7]
^Robin Matthewman (April 28, 2021). "Mark B. Feldman [Interview]"(PDF). Association for Diplomatic Studies and Training, Foreign Oral History Collection.
