(FORTUNE Magazine) – In Washington, you can never have too much of a good thing. Take empowerment zones. In 1993 these targeted tax breaks were a way to lure businesses back to inner cities. But rural lawmakers cried, "What about us?" So they got similar incentives. Soon, native Americans complained too and were added to the list. Then came Oklahoma, which boasts more native Americans than any other state, but no Indian reservations. The solution: give the tax breaks to "former Indian reservations in Oklahoma." The only problem was that two-thirds of Oklahoma, including Tulsa, became an Indian reservation for tax purposes.

Congress tried to fix the error earlier this year, but companies like Williams and Southwestern Bell were too quick: They already had claimed the tax breaks--which will save them and their fellow Oklahomans an estimated $12 million over two years. The companies said it wasn't fair for Uncle Sam to be an, um, Indian giver--and believe it or not, the lawmakers concurred. The loophole was tightened, but those who took sanctuary in the reservation clause kept their tax savings.

--Jeffrey H. Birnbaum