A suspected terrorist accused of conspiring to assassinate President Bush said he proposed the plot but it wasn't pursued, and he was frustrated that other members of his al-Qaida cell lacked initiative, according to prosecutors. A government motion unsealed this week by a federal judge reveals new details in the case against Ahmed Omar Abu Ali, 24, who is scheduled to go on trial next month. Prosecutors say the Falls Church resident has admitted joining al- Qaida while attending college in Saudi Arabia and that he discussed numerous terrorist plots, including plans to assassinate Bush and hijack airplanes. Abu Ali...