Title 10 of the US Code encompasses the laws for the military and the Defense Department. Title 50 has the laws for espionage, intelligence, the National Security Council and war powers. An amendment I helped my then-boss write nearly four decades ago required that, if the CIA wanted to conduct a covert operation, the President had to give formal approval and the Congress had to be notified. That law, slightly revised, is still on the books. It's codified under Title 50, though the amendment was to a foreign aid bill, which is mostly codified under title 22.
Defense Secretary Rumsfeld saw an opening to use military forces for secret operations that Congress wouldn't have to be notified about, as David Ignatius discussed recently. He also notes some post-Rumsfeld reforms. In recent years, including the operation that killed Osama bin Laden, the intelligence communities paramilitary forces and the Pentagon's special operations forces have collaborated very effectively.
Several members of Congress, Democrats and Republicans, have expressed interest in broadening the Hughes-Ryan amendment to cover DOD-run covert operations with what some call a "Title 60" provision, covering operations whether conducted by Title 10, Title 50, or combined forces. This is an encouraging example -- at a time when there are so many discouraging ones -- of bipartisan cooperation to assure accountability in national security activities.