what does“separate exchange system”here mean?
The Department was also burdened by dozens of redundant systems with little or no justification. There were three separate exchange systems, but we couldn’t consolidate them without the approval of Congress. There were three different health-care systems and three surgeons general—one for each military service. While civilian control of the military was one of the founding principles of our country, the way DoD was organized and overseen by Congress made it exceedingly difficult for any Secretary to conduct and be responsible for the business of the Department.