Felicia Ellsworth has built a distinguished portfolio of work in the Litigation/Controversy Practice Group as a member of both the Appellate & Supreme Court Litigation Group and Business Trial Group. Her trial practice focuses on high-stakes complex commercial litigation in both state and federal courts, and her appellate practice spans both civil and criminal matters in the state and federal appeals courts, including the Supreme Court of the United States.
Ms. Ellsworth has counseled numerous clients in commercial disputes on issues including patent infringement, trade secret misappropriation, contract law, civil procedure, real property disputes, tort law, administrative law and procedure, and constitutional law. She has also counseled and represented clients in both civil and criminal appeals involving patent infringement, contract law, constitutional law, and criminal law and procedure. Ms. Ellsworth has represented clients in Massachusetts and other state trial and appellate courts, including the Supreme Judicial Court, in administrative tribunals, as well as in federal district courts and in the United States Courts of Appeals for the First, Second, Fourth, Fifth, Sixth, Ninth, Tenth, and Federal Circuits, and the Supreme Court. She has argued before both federal and state appeals courts, including the First, Second, and Sixth Circuits and the Massachusetts Appeals Court.
- Defending against putative class action lawsuits in federal and state court arising out of a recent highly publicized data breach.
- Representing multinational networking equipment manufacturer in a patent infringement appeal in the Federal Circuit and Supreme Court, in a case argued in the Supreme Court in March 2015.
- Helped lead the WilmerHale team in filing a brief in Obergefell v. Hodges, concerning government recognition of the freedom to marry, on behalf of a total of 303 Republican, libertarian, conservative and center-right high-profile activists and government officials, including past presidential candidates, seven current and former governors, and 23 current and former members of the House of Representatives and US Senate. The brief received significant media attention when filed.
- Representing a private beverage company in the Ninth Circuit and Supreme Court in an important Lanham Act case, resulting in a unanimous ruling in the client's favor in a case that attracted significant press coverage, including in The New York Times and Law360.
- Helped lead the WilmerHale team in filing amicus briefs on behalf of Gay & Lesbian Advocates & Defenders in the Fourth, Fifth, Sixth, Seventh, and Tenth Circuits in appeals arising out of challenges to same-sex marriages bans in several states. Ms. Ellsworth and the team have argued that these bans cannot survive rational-basis review because the proffered rationales for the ban either lack a rational connection to the bans or are based on illegitimate purposes, or both.
- Representing a multi-national oil and gas company in several matters as part of a litigation in which tens of billions of dollars in damages are sought from energy industry companies based on allegations that oil and gas development work over many decades has damaged coast property in Louisiana and made it more vulnerable to flood damage.
- Leading the WilmerHale team representing the State of Vermont in a matter involving the proposed relicensing of the Vermont Yankee Nuclear Power Station in administrative relicensing proceedings before the Vermont Public Service Board. The proceeding spanned approximately 18 months and culminated in a combined five weeks of hearings in 2013.
- Representing a medical device manufacturer in a successful appeal to the Supreme Judicial Court of Massachusetts involving damages and injunctive relief.
- Presented oral argument on behalf of appellee American Honda in W&D Imports Inc. v. Lia. Five days after oral argument, the panel issued a summary order affirming the decision in American Honda's favor.
- Ms. Ellsworth has filed numerous amicus curiae briefs in both in the Supreme Court, Federal Circuit and other courts of appeals addressing a variety of different topics. Most recently, Ms. Ellsworth filed an amicus brief in support of certiorari on behalf of a group of Internet industry companies in Spokeo Inc. v. Robins.
- Helped lead a team of WilmerHale lawyers that began representing the Commonwealth of Massachusetts in 2009 as co-counsel in its challenge to the constitutionality of DOMA, the first in the nation. Both the District of Massachusetts and the First Circuit struck down DOMA as unconstitutional—marking the first ruling by a federal appeals court striking down DOMA. These decisions were later confirmed by the Supreme Court's decision in United States v. Windsor. In the Windsor case, Ms. Ellsworth once again helped lead a WilmerHale team in filing an amicus brief on behalf of more than a dozen former Solicitors General of the United States, White House Counsel, and heads of the Office of Legal Counsel explaining that the Supreme Court has jurisdiction to hear a case challenging DOMA even though the federal government did not defend the law. The Court's jurisdictional ruling was essential to its ultimate decision to strike down DOMA.
- Helped lead the WilmerHale team in filing a brief in Hollingsworth v. Perry, challenging the constitutionality of California's Proposition 8, on behalf of more than 100 prominent Republicans, including top advisers to former President George W. Bush, seven former governors, and 12 current and former members of Congress. The brief received significant media attention that included coverage by The Wall Street Journal, National Law Journal and Law360.