Jose Posada Carriles is quite a prolific terrorist. He bombed a Cuban civilian airliner in Venezuela, but this is among the least of his crimes. Far more horrendous was his involvement in arming the Nicaraguan Contras. Terrorist action against Nicaragua was condemned by a World Court decision, a U.N. General Assembly Resolution, and Security Council resolutions if you ignore the U.S. veto.
He managed to escape a Venezuelan prison and enter the U.S. illegally. Venezuela requested his extradition. But this was a problem for the U.S. as explained in the "liberal" Boston Globe.
After his escape from a Venezuelan prison, Posada Carriles was hired by US covert operatives to direct the resupply operation for the Nicaraguan contras from El Salvador. Extraditing him for trial could send a worrisome signal to covert foreign agents that they cannot count on unconditional protection from the US government, and it could expose the CIA to embarrassing public disclosures from a former operative. It also would infuriate some members of Florida's Cuban exile community who gave George W. Bush crucial support in both his presidential election victories.
Tough choice. On the one hand you've got a terrorist. On the other you don't want to discourage CIA covert action (more terrorism). What to do? Well, the courts decided to reject Venezuela's request. Today Carriles lives in Miami with his wife.
A day following the court's decision FBI director Robert Mueller asked Europe to speed their extradition process. Here is how it is reported in the Financial Times.
“We are always looking to see how we can make the extradition process go faster,” Mr Mueller told the FT. “We think we owe it to the victims of terrorism to see to it that justice is done efficiently and effectively.”