; and (D) the number of trained, full-time administrative staff by 3. (3) Immigration attorneys (A) Office of the principal legal advisor attorneys By not later than September 30, 2021, in addition to positions authorized before the date of the enactment of this Act and any existing attorney vacancies within the Department of Homeland Security on such date of enactment, the Director of U.S. Immigration and Customs Enforcement shall increase the number of trained, full-time, active duty Office of Principal Legal Advisor attorneys by not fewer than 1,200. The majority of such attorneys shall perform duties related to litigation of removal proceedings and representing the Department of Homeland Security in immigration matters before the immigration courts within the Department of Justice, the Executive Office for Immigration Review, and enforcement of U.S. customs and trade laws. At least 50 of these additional attorney positions shall be by the Attorney General to increase the number of U.S. Immigration and Customs Enforcement attorneys serving as Special Assistant U.S. Attorneys, on detail to the Department of Justice, Offices of the U.S. Attorneys, to assist with immigration-related litigation. (B) USCIS immigration attorneys By not later than September 30, 2021, in addition to positions authorized before the date of the enactment of this Act and any existing attorney vacancies within the Department of Homeland Security on such date of enactment, the Director of U.S. Citizenship and Immigration Services shall increase the number of trained, full-time, active duty Office of Chief Counsel attorneys by not fewer than 250. Such attorneys shall primarily handle national security and public safety cases, denaturalization cases, and legal sufficiency reviews of immigration benefit decisions. At least 50 of these additional attorney positions shall be used by the Attorney General to increase the number of U.S. Citizenship and Immigration Service attorneys serving as Special Assistant U.S. Attorneys, on detail to the