The jury in U.S. District Court convicted Ahmed Omar Abu Ali, 24, of Falls Church, Virginia, on all nine counts after 2 1/2 days of deliberation. The charges include conspiracy to assassinate the president, conspiracy to hijack aircraft and providing material support to al Qaeda.
The charges carry a possibility of life in prison and a mandatory minimum sentence of 20 years, prosecutors said. Sentencing is scheduled for Feb. 17.
CBS News correspondent Barry Bagnato reports that the defense argued that a coerced confession in a foreign country should not be the basis for bringing a case against an American citizen in U.S. courts. Eventually, that issue could wind up before the Supreme Court.
Abu Ali's lawyer, Khurrum Wahid, said he will appeal.
Abu Ali "is disappointed that the jury didn't see the truth and he wants us to continue the fight," Wahid said after the verdict.
Wahid said he believes it's difficult for any person to get a fair trial when the accusations involve al Qaeda.
"I think the country went through a very traumatic event on Sept. 11 and it's very difficult for people to separate that from the facts in a particular case," he said.
Jurors in the three-week trial saw a videotaped confession Abu Ali gave to the Saudis in which he said he joined al Qaeda because he hated the United States for its support of Israel. Notes taken by Saudi interrogators showed that he discussed numerous potential terror plots, but the one that most appealed to him was killing "the leader of the infidels" — President Bush.
Defense lawyers argued, though, that Abu Ali gave a false confession after being whipped and beaten by members of the Saudi security force known as the Mubahith.
Juror Nancy Ramsden said the videotaped confession was a "very striking" piece of evidence for her.
"It was very telling. It was almost sort of a joke for him," she said, referring to points in the tape where Abu Ali laughs and pantomimes the use of an assault rifle.
Ramsden said the jurors agreed from the beginning that they did not believe Abu Ali was physically tortured, but some jurors had initial questions about mental torture.