The Rev Jesse Jackson has had a string of successes in securing the release of Americans held abroad.
In the run-up to the Gulf War in 1991 he persuaded President Saddam Hussein of Iraq to release about 500 foreigners of various nationalities who were being detained as "guests" of the regime.
In 1984 the civil rights leader, who has had presidential ambitions, negotiated with Syria the release of a US navy pilot who had been shot down in a raid on Lebanon.
in the same year, he persuaded President Fidel Castro to release 22 Americans and 26 Cubans from prison on the island.
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He has also helped settle several labour disputes in the US, when he sided with the workers and embarrassed employers into conceding their demands.