The Federal Circuit Court, which hears most patent cases, says there must be some kind of "motivation or suggestion" in the prior art that suggests the combination, otherwise a patent will be awarded. For your information this is informally called the "teaching, suggestion, or motivation" test.

Until now the test has been interpreted quite liberally, meaning patents have been awarded in most cases because the Circuit Court made the burden to establish "motivation in the prior art to combine" tough to prove.

Enter Microsoft and Cisco as amicus (or "amici" if you prefer the plural). If KSR wins, both attorneys I spoke with expect the Supreme Court to tighten the "teaching, suggestion, or motivation" test or come up with one of their own.

Either way the Supreme Court will make it easier to prove obviousness and harder to receive a patent for a product or for a business method that combines current technology.

Saunders believes companies like Microsoft and Cisco are willing to give up some of their patent protection and rely instead on their market clout in order to reduce the number of patent infringement cases they must address each year.