II 116th CONGRESS 1st Session S. 401 IN THE SENATE OF THE UNITED STATES February 7, 2019 Mr. Markey (for himself, Mr. Merkley , Mrs. Feinstein , Ms. Warren , Mrs. Gillibrand , Mr. Van Hollen , Mr. Murphy , and Mr. Sanders ) introduced the following bill; which was read twice and referred to the Committee on Armed Services A BILL To prohibit the research and development, production, and deployment of the Trident D5 low-yield nuclear warhead, and for other purposes.