Just how worn out are our troops because of non-stop combat since 9/11? To what degree has that contributed to problems like PTSD, family breakups and suicide in the ranks? This week, on Command Post, we discuss the tenacity of U.S. troops, as well as the cracks that can appear after a decade of fighting. Margaret Harrell, a military manpower expert at the Center for a New American Security, and Eric Schmitt of the New York Times -- co-author of Counterstrike: The Untold Story of America's Secret Campaign Against al Qaeda, tackle these tough issues. Joining me is John Nagl, CNAS president and retired Army officer.