From Key West to Havana is 145 kilometres of open sea — closer than New York is to Philadelphia, and less than a normal fighter jet's combat radius. Cuba is not a distant Caribbean island from the American point of view. It is, in the strictest geographic sense, part of the southern approach to the US mainland, dominating the Straits of Florida through which most shipping to and from the Gulf of Mexico must pass. This basic proximity has shaped US policy toward the island since Thomas Jefferson, who wrote in 1823 that Cuba's annexation would 'fill up the measure of our political well-being'. Every administration since — Democratic and Republican, hawk and dove — has treated a hostile foreign power on Cuba as a direct threat to the American homeland. Geography wrote this rule long before ideology decorated it, and no shift in Washington politics has ever managed to erase it.
In December 1823, President James Monroe delivered an annual message to Congress that included a clause his Secretary of State John Quincy Adams had largely drafted: any further European attempt to colonise or interfere with the independent nations of the Americas would be treated as 'the manifestation of an unfriendly disposition toward the United States'. At the time, the young republic could not have enforced this on its own — it was the Royal Navy, not the US, that actually deterred European reconquest, because Britain wanted access to newly-independent Latin American markets. But over the following century the Monroe Doctrine hardened from a bluff into an operating system. Theodore Roosevelt's 'Corollary' in 1904 added an explicit right of US intervention in the Western Hemisphere. Between 1898 and 1934 alone the US Marines occupied Cuba, Nicaragua, Haiti, the Dominican Republic and parts of Mexico. The pattern is remarkably durable: American administrations tolerate an enormous range of behaviour in Latin America, but not the presence of a rival great power.
The Spanish-American War of 1898 was the moment the doctrine became imperial architecture. In ten weeks, the US destroyed Spain's Caribbean and Pacific fleets and took Cuba (militarily), Puerto Rico, Guam and the Philippines. Cuba was granted formal independence in 1902, but only after Washington attached the Platt Amendment — a set of clauses in the Cuban constitution that gave the US the right to intervene militarily whenever it saw fit and to lease a permanent naval station at Guantánamo Bay. That lease, at a nominal rent of around $4,000 a year, has never been cancelled. The base still flies the American flag; the annual cheques from Washington are, by long tradition, never cashed by Havana. From 1898 the Caribbean was, in the phrase of American strategists at the time, an 'American lake' — a bounded sea within which US warships operated as a matter of routine, and outside powers stayed out.
In April 1959, Fidel Castro's revolution overthrew a US-backed dictator. Over the next two years, Havana nationalised American businesses and drifted into the Soviet orbit. The Bay of Pigs invasion of April 1961 — an underpowered CIA operation using Cuban exiles — failed within three days. Emboldened, Nikita Khrushchev secretly deployed medium-range nuclear missiles and Il-28 bombers to the island in the summer of 1962. When American U-2 flights photographed the missile sites on 14 October, President Kennedy faced the exact scenario every US strategist had feared since the doctrine's inception: a rival great power's warheads sitting on the far side of the Straits of Florida, capable of hitting Washington within minutes of launch. For thirteen days the world came closer to nuclear war than at any point before or since. The public deal was a Soviet withdrawal in exchange for a US pledge not to invade; the secret deal included the removal of American Jupiter missiles from Turkey. The Kremlin blinked in Havana. Washington, quietly, blinked in Ankara.
Six decades after the missile crisis, the US embargo on Cuba is still in place — one of the longest continuous economic sanctions programmes in modern history. Every president since Kennedy has kept it, tightened it, or made cosmetic adjustments. Obama's 2014–2016 opening restored diplomatic relations and eased travel; Trump I reversed most of it; Biden made small adjustments; Trump II has hardened it again. The strange durability of the policy is not really about the Castros or communism. It is about the doctrine. The US treats Cuba as a special case not because Havana poses a direct military threat to Miami — it plainly does not — but because tolerating one openly hostile regime ninety miles from Florida sets a precedent that other governments in the hemisphere might follow, and other great powers might exploit. A friendly, or at minimum non-aligned, Cuba is treated in Washington as a permanent strategic interest, held across every partisan swing, waiting out any regime.
In June 2023, the Wall Street Journal reported — confirmed by US intelligence officials — that China had built a signals-intelligence facility in Cuba capable of eavesdropping on communications across the American south-east, including the space and submarine launch sites in Florida. Follow-up reporting suggested a training facility and possibly additional listening posts. Beijing denied it. Havana denied it. Washington, discreetly, treated it as fact. What matters here is the historical rhyme. In 1962 the rival great power was Soviet, the payload was warheads, and the platform was concrete missile silos. In 2023 the rival great power is Chinese, the payload is data, and the platform is fibre optics and antennas. The medium has changed; the doctrine has not. Ninety miles is still ninety miles, and every serious American analyst reads the Chinese presence in Cuba through the same lens the Kennedy White House used sixty years earlier.
Tim Marshall puts it about as cleanly as it can be put in 'Prisoners of Geography': the United States will accept almost any regime in Cuba — left, right, capitalist, socialist, competent, corrupt — provided it is not aligned with a rival great power. That is the whole rule. It explains why the embargo persists under Democratic administrations, why the door opens whenever Havana looks like it might drift toward genuine neutrality, and why it slams shut the moment a Russian bomber lands at José Martí airport or a Chinese antenna appears on the north coast. The island is not, and never has been, a target of American territorial ambition. It is a red line drawn by geography — one of the oldest and most consistent lines in American foreign policy — and no administration, left or right, populist or establishment, has ever seriously considered crossing it.
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