The broken American patent system has a knack for sanctioning the ridiculous. In the latest example, businesses are receiving patents for devising ways to pay less tax. What's next, a patented murder defense?  As Floyd Norris reported recently in The New York Times, the broad category known as business-method patents (like patenting the idea of pizza delivery rather than the pizza itself) has expanded once again. Now it includes the legal ways that accountants and lawyers help their clients prepare their tax returns.  Once the Patent and Trademark Office has granted one of these patents, everyone who uses the same legal shelter - even if they draw the conclusion based on their own interpretation of the tax code - will be subject to lawsuits and even injunctions against using the method at all.  Defenders of these tax-strategy patents argue that they won't affect the average person's struggle with the tax form. The easy stuff should be rejected under the usual standard that requires patents to be novel and not obvious. Tax-strategy patents, they argue, are more geared toward the complicated tax returns of the rich.  While we don't normally rush to make it easier for the rich to pay less tax, the precedent is a bad one. People should be treated the same under the law, and shouldn't have to pay a licensing fee for the privilege. Congress needs to make spurious patents easier to challenge across the board, and should consider clarifying what may be patented. Recent technological advances raise questions about how patents apply to genes and life forms, or what standard should cover old business models on the Internet.  Patents are supposed to encourage innovation, rewarding the individual for the greater good of society. But overly broad patents can slow business activity to a snail's pace. And we sure don't need something else to worry about on tax day.