In its ruling, the U.K. House of Lords dismissed McKinnon's claim that the disparity in possible penalties for cooperating (three to four years) with U.S. prosecutors and contesting U.S. charges (at least eight to 10 years) subjects him illegal pressure to surrender his legal rights under U.K. law.
If the extradition goes forward, McKinnon will be tried in the United States. It's not clear what sentence U.S. prosecutors would seek if McKinnon is convicted. A BBC report suggests McKinnon faces up to 60 years if U.S. authorities try McKinnon as a terrorist. Other reports cite a figure of 70 years.
But in the House of Lords Judgment, Lord Brown of Eaton-Under-Heywood said, "He might serve a total of only some 18 months to two years."
McKinnon's attorneys have asked the European Court of Human Rights to intervene. A decision in the matter is expected in 10 to 20 days.
McKinnon was arrested in the United Kingdom in 2002, but the country's Crown Prosecution Service declined to charge him. He was charged later that year by the United States.
McKinnon is alleged to have deleted data from U.S. military systems and disrupted military operations. His activities are estimated to have cost $700,000 in damage.
McKinnon claims that he was motivated by the desire to uncover information about UFOs.
In an interview with the BBC conducted after the ruling, McKinnon described his actions as a moral crusade. "[UFOs] have been reverse-engineered," he said. "Rogue elements of Western intelligence and governments have reverse engineered them to gain free energy, which I thought was very important, in these days of the energy crisis."
Other sources suggest a motive more political than altruistic. According to the House of Lords Judgment, McKinnon admitted leaving a note on one Army computer that said, "U.S. foreign policy is akin to government-sponsored terrorism these days ..."