In late September, while the major presidential candidates debated solutions for reforming the federal corporate income tax, a little-noticed ruling by the Internal Revenue Service (IRS) opened the door for widespread corporate tax avoidance by a few of the biggest, most profitable financial institutions in the country. The IRS ruling, which took Congressional tax writers by surprise, will almost certainly push the federal government -- and many states -- further into the red at a time when they can least afford it.