Ressam was arrested in December 1999 as he drove off a ferry from Canada into Washington state with a trunk full of explosives. U.S. District Judge John C. Coughenour had twice ordered him to serve 22-year terms, but both times the sentences were reversed on appeal.
Ressam's attorneys had conceded that he should face at least three decades to satisfy the appeals courts, but no more than 34 years.
The Justice Department had sought life in prison because of the mass murder he intended to inflict, and because he recanted his cooperation with federal investigators.
Assistant U.S. Attorney Ausa Helen Brunner argued Ressam continues to pose a threat, as evidenced by his recantation of prior cooperation.
Ressam's lawyer, Thomas Hillier, disagreed, pointing to a letter Ressam sent the judge this week in which he wrote: "I am against killing innocent people of any gender, color or religion. I apologize for my actions."
Ressam, who made a similar statement to the court in 2003, did not speak at the hearing Wednesday.
Coughenour said Wednesday that this "this case provokes our greatest fears."
An alert customs official in Port Angeles on the Olympic Peninsula noticed that Ressam appeared suspicious when he drove from a ferry from British Columbia on Dec. 16, 1999, and signaled him to stop for further inspection. His arrest, after a brief foot chase, prompted fears of a terrorist attack and the cancellation of Seattle's New Year's Eve fireworks.
Ressam's case has been vexing because he started cooperating after he was convicted and was interviewed more than 70 times by terror investigators from the U.S., Canada, Great Britain, Spain, Italy, Germany and France. Information he provided helped convict several terror suspects; prompt the famous August 2001 FBI memo titled "Bin Laden determined to strike in U.S.;" and contribute to the arrest of suspected Osama bin Laden lieutenant Abu Zubaydah, who remains in custody without charges at Guantanamo Bay, Cuba.
However, Ressam subsequently recanted all of his cooperation when it became clear that the prosecutors weren't going to recommend that he serve less than 27 years in prison. The recanting forced the Department of Justice to drop charges against two suspected co-conspirators, Samir Ait Mohamed and Abu Doha.
In previously sentencing Ressam, Coughenour noted that before he went to trial, the government offered him a 25-year sentence if he would plead guilty - no cooperation necessary. Ressam refused, but Coughenour said that any discount for Ressam's cooperation, while it lasted, should start from that 25-year offer.
The appeals court rejected that rationale.