The enemy without who has seen off nine US presidents

They indirectly triggered the worst nuclear stand-off of the Cold War. They caused an international tug of war over the fate of a little boy, which may have helped to tip the 2000 presidential election to George Bush. One way or another, the fraught relations between the US and Castro's Cuba have shaped the course of recent history.

In the 47 years of rule that have made him the world's most durable head of government, Fidel Castro has locked horns with 10 US presidents. He has survived an invasion, a naval blockade, and decades of diplomatic isolation and economic sanctions - not to mention, by Havana's account at least, hundreds of US-backed attempts to assassinate him.

Dwight Eisenhower was in the White House when Mr Castro took power in 1959. He recognised the new regime in Havana. But ties soon grew frosty, as Cuba nationalised US-owned assets and established relations with Moscow in 1960.

Just before leaving office, Eisenhower broke off relations. His successor, John F Kennedy, quickly took matters further, authorising the Bay of Pigs invasion of April 1961. The invasion by Cuban exiles was a fiasco, and within a year Moscow was stationing nuclear weapons in Cuba. The result was the 1962 Cuban missile crisis.

Kennedy eventually stared down the Soviet threat, but maintained an economic and travel embargo. His successor, Lyndon Johnson, eased some restrictions, allowing up to 4,000 Cubans a month to emigrate to the US, in an eight-year deal, cancelled when Richard Nixon was President.

The next brief thaw came under Jimmy Carter, who reinstated limited diplomatic ties with the island. But the mood soured with the 1980 Mariel boatlift when 125,000 Cubans, including many criminals, arrived in the US in a mass exodus engineered by Mr Castro. Ronald Reagan reimposed the ban on travel by US citizens to Cuba that Mr Carter had lifted.

The next big crisis came in 1996, when the Cuban military shot down two small planes carrying four members of a Cuban exile group, killing all of them. Months later, President Bill Clinton signed the Helms-Burton Act, tightening the embargo, and punishing anyone (foreigners included) who exploited assets confiscated by the regime.

Four years later came the affair of Elian Gonzalez, the five-year-old boy picked up off the Florida coast, the lone survivor of a group of 13 would-be immigrants. After a legal battle, the Clinton administration sent him back to his father in Cuba, despite furious opposition from the exile community in Florida. The decision may have helped to tip Florida, the crucial state in the 2000 election, away from Al Gore.

Mr Bush lost little time in tightening the embargo. He limited travel and remittances sent by Cuban-Americans to their families on the island, and boosted US propaganda. He denounced Mr Castro as a "tyrant" and "a relic from another era". Even now however, if the "relic" is at last swept away, it will be due to human frailty, rather than the efforts of the White House.

American opponents

Dwight Eisenhower 1953-61

John F Kennedy 1961-63

Lyndon Johnson 1963-69

Richard Nixon 1969-74

Gerald Ford 1974-77

Jimmy Carter 1977-81

Ronald Reagan 1981-89

George Bush Snr 1989-93

Bill Clinton 1993-2001