When you say "Congress and the courts" the truth is "only the Federal Circuit Court". The Supreme Court of the United States' best interpretation of patent statute is that software for a general-purpose digital computer is not statutory material for a patent. See http://ourdoings.com/ourdoings-startup/2011-07-28

And now that the Fed Circuit in the Bilski case has backed off a bit from their flagrantly wrong In re. Alappat decision and its affirmation in State Street, one could argue that there isn't any court left claiming that software for general-purpose digital computers is patentable.