A former high school valedictorian accused of joining Al-Qaeda and plotting to assassinate President Bush pleaded innocent yesterday in federal court to providing material support to terrorists and other charges. An Aug. 22 trial date was scheduled for Ahmed Omar Abu Ali, 23, of Falls Church. He was indicted last month and charged with six counts that would allow a maximum prison term of 80 years. Prosecutors say Abu Ali, a US citizen who was valedictorian of his class at an Islamic private school in northern Virginia, joined Al-Qaeda while studying overseas in Saudi Arabia. An FBI agent testified that Abu Ali admitted his guilt multiple times in interviews with Saudi and American authorities, but Abu Ali's lawyers say the government's evidence was obtained through torture and that they have seen the scars on Abu Ali's back from the beatings. The counts against Abu Ali include two counts of conspiring to provide material support to terrorists, two counts of providing material support to terrorists, one count of contributing services to Al-Qaeda and one count of receiving funds and services from Al-Qaeda. Prosecutors say he discussed numerous terrorist acts with other Al-Qaeda members, including a plan in which he would either shoot President Bush or detonate a car bomb.