Redesignates existing paragraphs (3)–(6) as (4)–(7) and inserts a new paragraph (3) authorizing eligible members to participate in congressional fellowships under the subsection with specified offices and conditions, including approval by the host office, limits on concurrent fellows (with limited 14-day overlap), consultation with commanding officer, an orientation requirement in consultation with the Assistant Secretary of Defense for Legislative Affairs, notification to that Assistant Secretary, and a 180-day maximum fellowship duration.