The case has acquired significance way beyond these mere facts, however, taking in successive administrations in the U.S. and the U.K., and becoming politically controversial in light of the U.K.'s 2004 enactment of its extradition agreement with the U.S.

McKinnon's extradition depends on two decisions. First, U.K. Home Secretary Theresa May must review evidence on his medical fitness to face extradition, a decision on which is imminent. If ruled fit, McKinnon will then be subject to a judicial review into the case granted on appeal against the 2009 decision by former Home Secretary Alan Johnson to allow his extradition to proceed.

If either rules in his favor, McKinnon will stand trial in the U.K. under less draconian sentencing guidelines.

McKinnon's mother, Janis Sharp, who has campaigned for her son to stand trial in the U.K., welcomed President Obama's remarks.

"The fact that two such powerful men had four questions [in the press conference] and one of them was all about Gary, it was overwhelming ... that they took the time to talk about Gary was incredible," she was reported to have said.