The Supreme Court today reversed the Federal Circuit's ruling, in a 9-0 decision authored by Justice Breyer. The Court clarified that the patentee always bears the burden of proving infringement, even in situations where the accused infringer agreed to a license in the past. Three legal rationales were relied upon for this conclusion. First, the traditional rule and precedent is that the plaintiff patent holder generally bears the budren of proof. Second, the Declaratory Judgment Act is "only procedural, leaving substantive rights unchanged." Third, and coming full circle, "the burden of proof is a substantive aspect of a claim."
Interestingly, underpinning the Supreme Court's decision were also two policy based notions. One is the notion that the patentee is in a better position than the alleged infringer to know, and to be able to point out, just where, how, and why a product (or process) infringes a claim of a patent. Another is that the public interest is best served by maintaining a mechanism for challenging patent rights, in order to maintain a balanced and well-functioning patent system and to keep patent monopolies within their legitimate scope.
Today's decision is the first of a number of patent cases that will be heard by the Supreme Court this year. Stay tuned for Alice v. CLS Bank, a case assessing the proper test for software patent eligibilty under Section 101, Limelight Networks v. Akamai Technologies involving issues of divided infringement, Nautilus v. Biosig Instruments regarding the proper standard for indefiniteness under Section 112, as well as Highmark v. Allcare and Octane Fitness v. Icon Health, two cases directed to the award of attorneys fees in exceptional patent cases under Section 285.
For the complete court opinion -- http://www.supremecourt.gov/opinions/13pdf/12-1128_h315.pdf