Thirty-four people were convicted yesterday of misdemeanor charges stemming from a demonstration at the Supreme Court in January in which they decried conditions at the U.S. military prison at Guantanamo Bay, Cuba.

    DC Superior Court Judge Wendell P. Gardner Jr. said the demonstrators violated the law by protesting at the plaza of the Supreme Court, where such activities are banned. He rejected arguments that they were practicing free speech when they marched to the plaza, despite warnings from police, carrying banners and wearing T-shirts saying "Shut down Guantanamo."

    The demonstration occurred Jan. 11, the sixth anniversary of the opening of the detention facility, which was set up to house terrorism suspects. During a three-day trial, prosecutors presented a videotape that showed several officers warning the protesters to remain on the sidewalk, where demonstrations are legal, or risk arrest.

    During the trial, many of the 21 men and 13 women wore orange jumpsuits to show solidarity with Guantanamo detainees. When the defendants spoke, they gave their name and then the name, age and a brief biography of someone they described as a Guantanamo detainee. Many wore a tag bearing the name of a detainee.

    As Gardner began explaining his ruling, one of the defendants, Paul Magno of the District, stood up and turned away from the judge. Gardner ordered a marshal to arrest Magno for contempt of court. Magno was escorted out, but not before shouting to the judge: "You have committed a crime against justice."

    The judge ordered all defendants to return to court today for sentencing. Each faces up to 60 days in jail. Gardner said most will probably get probation. Those who had prior convictions, mostly for civil disobedience or disturbing the peace, could be jailed, Gardner said, to stop them from doing "the same thing over and over."

    Because the charges were misdemeanors punishable by less than six months in jail, the case was heard by a judge instead of a jury.

    After the decision, several defendants said they weren't surprised by the ruling but were pleased that they could voice their concerns about Guantanamo in court.

    "We're sad about the convictions, but we're happy, moved and humbled to bring the stories, names and identification of the men in Guantanamo into a court of law," said Frida Berrigan, 34, of Brooklyn. She is the daughter of the late Philip Berrigan, a former Roman Catholic priest who was a major figure in the American peace movement during the Vietnam War.

    The protesters are part of a group called Witness Against Torture, which has held demonstrations across the country condemning the prison. Members range in age from 19 to their early 70s.

    The defendants represented themselves at trial, and their closing arguments drew emotional responses from each other and from supporters in the courtroom. Several wiped away tears as two defendants spoke on behalf of the group, citing the actions of Martin Luther King Jr. and others.

    Earlier in the trial, the judge had dismissed charges against a 35th defendant because he said he had not been conclusively identified by police in a review of the videotape.

    Before Gardner issued his ruling yesterday, one of the defendants stood and asked for a moment of silence for the detainees. Assistant U.S. Attorney Magdalena Acevedo quickly jumped to her feet to object.

    "Your honor, this is a court of law. And no matter what we may think of their personal beliefs, it does not justify them violating the law," Acevedo said.