Cooper v. Square is the final pending constitutional challenge to the inter partes and post grant review proceedings created by Congress in the America Invents Act of 2011 and briefing in the case is now complete.
In the final reply brief in the petition process, Cooper explains how this case is a good vehicle for the challenge:
This case is the only one left of three that raised a facial constitutional challenge to inter partes review (IPR). This Court relisted in Cooper v. Lee, No. 15-955, and MCM Portfolio v. HP, No. 15-1330, before denying cert on October 11, 2016. This case is distinct from both of those, and far more amenable to adjudication by this Court. This case does not have the vehicle problem identified by the federal respondent in Cooper v. Lee (since this case arises directly from an agency final decision, whereas Cooper v. Lee arose from a collateral proceeding). And this case does not seek the extreme constitutional remedies of the petitioner in MCM Portfolio (since this case seeks relief in the form of making IPR outcomes advisory, not in the form of annihilating an entire section of a federal agency).
In its responsive brief Square argued that Cooper waived his constitutional argument by not repeatedly raising the issue. The Cooper brief does a nice job of explaining the errors in that conclusion.
Patent Academic Ray Mercado also took advantage of the request for a responsive brief to file an amicus brief. Mercado argues that patents should be seen as “private rights” and therefore cannot be administratively cancelled. He writes: “Once the historical uniqueness of patent law is taken into account, it is clear that patents are ‘private rights’ for purposes of this Court’s separation of powers jurisprudence, and their validity must be decided by Article III courts.”