DOD chief says 9/11 bill could be devastating to US military

FILE - In this Sept. 22, 2016 file photo, Defense Secretary Ash Carter, accompanied by Joint Chiefs Chairman Gen. Joseph Dunford, testifies on Capitol Hill in Washington. As defense chief for a president who famously envisioned “a world without nuclear weapons,” Ash Carter has said remarkably little about them. He has been quiet on a range of nuclear issues, including the Pentagon’s efforts to correct an array of morale, training, discipline and resource problems in the Air Force nuclear missile corps. This is all the more notable for the fact that Carter, a physicist by training and policy wonk by reputation, cut his professional teeth on nuclear weapons during the Cold War. This quiet approach is expected to end when Carter visits Minot Air Force Base in North Dakota on Monday, Sept. 26, 2016. (AP Photo/Andrew Harnik, File) (The Associated Press)

Defense Secretary Ash Carter says legislation backed by the families of Sept. 11 victims could be devastating to the U.S. military.

Carter's concerns are detailed in a letter to a senior member of Congress that was released Tuesday.

Congress is poised to override President Barack Obama's veto of the bill that would allow the families to sue Saudi Arabia for the kingdom's alleged backing of the terrorists who carried out the 9/11 attacks. Obama has warned the legislation would make the U.S. vulnerable to retaliatory litigation in foreign courts that could put American troops in legal jeopardy.

Carter amplifies Obama's concerns. He says cases tried overseas could put the U.S. in the difficult position of having to choose between revealing secrets and suffering adverse rulings for refusing to do so.