Philip Tassin
Tel. (415) 773-6685


UC Berkeley School of Law, J.D., 2012

University of Pennsylvania, B.A., summa cum laude, 2007


Hon. Sidney R. Thomas
U.S. Court of Appeals for the Ninth Circuit, 2012-2013

Bar Admissions

U.S. Supreme Court

U.S. Court of Appeals for the Ninth Circuit

U.S. Court of Appeals for the Federal Circuit


Philip Tassin

Whether he’s representing major corporations in complex civil litigation, or fighting for an individual’s freedom, Mr. Tassin leverages a deep understanding of the details without losing sight of the big picture. Since joining Keker, Van Nest & Peters in the fall of 2013, Mr. Tassin has represented a variety of individuals and businesses in high-stakes litigation at both the trial and appellate levels, including disputes involving securities, breach of contract, breach of fiduciary duty, intellectual property, professional negligence, and the ever-changing landscape of medical marijuana. In each case, Mr. Tassin has guided his clients through uncharted legal territory and, where necessary, developed creative approaches to draw the boundaries in their favor. 

Mr. Tassin also maintains an active pro bono practice, working alongside the Electronic Frontier Foundation to challenge the National Security Agency’s warrantless surveillance of Internet users, and writing an amicus brief to the U.S. Supreme Court in support of the Affordable Care Act’s contraception coverage requirement.

Cases of Note

Ziptronix v. Taiwan Semiconductor Manufacturing Company: We won summary judgment of non-infringement for Taiwan Semiconductor Manufacturing Company, Ltd. and its subsidiary TSMC, North America in a long-running patent lawsuit brought by North Carolina semiconductor company, Ziptronix, Inc. Ziptronix had asserted nine patents and more than 500 patent claims directed to TSMC’s manufacturing of semiconductors for use in backside-illumination image sensors used predominantly in smartphone cameras. On behalf of TSMC, we defeated Ziptronix’s claims by arguing that the territorial limits of U.S. patent law prohibited reaching TSMC’s business transactions and manufacturing operations in Taiwan.

Payne et al. v. Office of the Commissioner of Baseball et al.: Plaintiffs filed a putative class action against Major League Baseball, the Commissioner, and the 30 Clubs demanding that our clients install protective netting from foul pole to foul pole at every Major League and Minor League ballpark. We moved to dismiss the case for lack of standing, lack of personal jurisdiction, improper venue, and failure to state a single claim for relief. The court granted our motion to dismiss.

United States v. Matthew Davies: After Congress passed a sweeping new law barring the federal government from impeding state medical-marijuana laws, we petitioned for a writ of habeas corpus to secure the release of Matthew Davies, who is serving a federal prison sentence for running nonprofit medical marijuana dispensaries that were compliant with California law. The case is currently on appeal to the U.S. Court of Appeals for the Ninth Circuit.

Shareholders v. Technology Company: We represent a cutting-edge medical technology company in a putative class-action lawsuit claiming that the company’s executives made various false and misleading statements regarding the company’s financial health and the safety of the company’s product. That case is currently at the class-certification stage. We also represent the same company in various real and threatened shareholder derivative lawsuits concerning the same subject matter.

Software Rights Archive v. LinkedIn and Twitter: After a non-practicing entity brought a patent-infringement lawsuit against our clients, we took advantage of the newly establish inter partes review procedure to invalidate 23 claims before the Patent & Trademark Office. The case is currently on appeal to the U.S. Court of Appeals for the Federal Circuit.

Plaintiffs v. National Security Agency: We represent AT&T customers pro bono in their suit challenging the U.S. government’s warrantless surveillance of electronic communications. Our clients assert that this surveillance violates their constitutional rights and various statutes designed to limit executive power. Following an appeal to the U.S. Court of Appeals for the Ninth Circuit, the case is currently in discovery before the district court.

Zubik et al. v. Burwell: On behalf of the American Academy of Pediatrics, we submitted an amicus brief to the U.S. Supreme Court in support of the U.S. Government in Zubik et al. v. Burwell, the challenge to the Affordable Care Act’s contraception coverage requirement.

Honors and Awards

UC Berkeley School of Law

  • Order of the Coif
  • Prosser Prize in Constitutional Law 
  • Prosser Prize in Professional Responsibility
  • Editor-in-Chief, California Law Review 
  • Associate Editor, Berkeley Technology and Law Journal
  • Best Oral Argument, First-Year Moot Court

University of Pennsylvania

  • Phi Beta Kappa
  • Distinction in Political Science


  • Why Treaties Can Abrogate State Sovereign Immunity: Applying Central Virginia Community College v. Katz to the Treaty Power, 101 Calif. L. Rev. 755 (2013).
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