A quarter of U.S. military facilities are falling apart, according to a new Senate report that comes on the heels of an unusually candid Pentagon document acknowledging about a third of Army and Air Force infrastructure is unneeded. The military could save an estimated $2 billion a year closing and consolidating facilities. But a base closing commission, or BRAC as it’s called, could trigger a huge, parochial fight in Congress over which facilities are targeted.