The Bush administration has studiously looked the other way while well-connected lenders have exploited a loophole in the student loan program that will reap them nearly a billion dollars in undeserved subsidies this year alone. Congress, which rakes in contributions from banks and other lenders, was reluctant to even discuss this problem until a public outcry recently made it impossible to avoid. The Education Department has claimed that it lacks the authority to close the loophole unilaterally. But that position was blown away this week in an unusually caustic report by the Government Accountability Office, which outlined the scope of the problem and urged the Education Department to solve it quickly.