Members of Debevoise & Plimpton LLP’s litigation department specialize in representing clients before the U.S. Supreme Court and other appellate courts. The Supreme Court & Appellate Practice is led by partner and White Collar Group Co-Chair David A. O’Neil, who previously clerked for Justice Ginsburg and served in the Solicitor General’s office. O’Neil’s most recent appearance before the Supreme Court was in 2022, when he argued Shoop v. Twyford, a habeas case involving the scope of a federal court’s authority under the All Writs Act. In 2019, O’Neil secured a unanimous victory in North Carolina Department of Revenue v. Kimberley Rice Kaestner 1992 Family Trust, in a dispute involving an attempt by North Carolina to tax a nonresident trust based solely on the fact that a beneficiary of the trust, who had not yet received any distributions, lived in the State.
Our Supreme Court and Appellate Practice has represented clients in a broad array of cases with a particular focus on issues of criminal and immigration law. The Debevoise team includes a deep bench of lawyers who have clerked at every level of the federal and state judiciary, served at the highest levels of the Justice Department, and secured significant victories in courts across the country. These lawyers have spent years honing their skills to develop persuasive briefs and oral argument strategies to navigate important cases in appellate courts, including the Supreme Court.
Because of our specialized experience, we are often retained by trial counsel to obtain Supreme Court review of an unfavorable decision in a federal court of appeals or state court of last resort. We also are frequently retained to oppose certiorari when in defense of a favorable decision. We excel working alongside co-counsel who bring years of case knowledge and specialized knowledge to these representations. Our highly collaborative approach and firm culture ensure that we deliver, alongside existing counsel, the best staffing and legal strategy for each case.
We advise clients at every stage of Supreme Court proceedings, including providing strategic advice to evaluate the likely success of a petition for certiorari.
Appellate Experience in Civil Cases ● Appellate Experience in Criminal Cases ● Appellate Experience in Immigration Cases ● Amicus Briefs
Appellate Experience in Civil Cases
Warren v. DeSantis: Secured district court victory on behalf of State Attorney Andrew Warren, after Florida Governor Ron DeSantis suspended him in violation of the First Amendment and the Florida Constitution for exercising free speech rights. Continued to represent Mr. Warren before the U.S. Court of Appeals for the Eleventh Circuit.
Brief in Support of Petitioners, Representative Ted Lieu, et al. v. Federal Election Commission, No. 19-1398 (filed Jul 22, 2020): Represented Senators Whitehouse, Leahy, Udall, Blumenthal, Hirono, and Van Hollen in support of Petitioners’ petition for a writ of certiorari over whether the federal statutory limit on contributions to political committees, 52 U.S.C. § 30116(a)(1)(C), comports with the First Amendment as applied to committees that make only independent expenditures.
Brief in Support of Respondents, The Little Sisters of the Poor Saints Peter and Paul Home v. Pennsylvania, et al., 591 US (2020), No. 19-431: Represented 186 Members of the United States Congress, including most of the Democratic caucus in the Senate, over whether the federal government had authority under the Affordable Care Act to promulgate rules exempting employers with religious or moral objections from providing contraceptive coverage to their employees.
Brief in Support of Respondents, David A. Zubik v. Sylvia Burwell, Secretary of Health and Human Services, et al., 578 U.S. (2016), No. 14-1418: Represented 123 Members of the United States Congress, including most of the Democratic caucus in the Senate, over whether religious institutions other than churches could be exempt from the Affordable Care Act’s contraceptive mandate.
North Carolina Department of Revenue v. Kimberley Rice Kaestner 1992 Family Trust: When North Carolina attempted to tax income from an out-of-state trust, the U.S. Supreme Court ruled that such taxation would constitute unjust confiscation of property in violation of the Due Process Clause. In this victory, the Debevoise team made a significant contribution to trust law. The UCLA Law Review called North Carolina Department of Revenue v. Kimberley Rice Kaestner 1992 Family Trust “the most important due process case involving trusts that the Court has decided in over sixty years.”
Tanzin v. Tanvir: Co-counseled on the issue of whether the Religious Freedom Restoration Act (“RFRA”) allows the plaintiffs to seek monetary damages from individual FBI agents who improperly placed or kept plaintiffs on the No-Fly List as retaliation for refusing to become informants on their Muslim communities.
United States Patent and Trademark Office v. Booking. com BV: Prevailed on behalf of Booking.com BV, one of the world’s leading digital travel companies, in its U.S. Supreme Court case – the first ever case argued by telephone in the Supreme Court – where the Court ruled 8-1 that Booking. com BV’s eponymous domain name is not generic and could register as a trademark.
Risley v. Universal Navigation Inc., No. 23-1340-CV, 2025 WL 615185 (2d Cir. Feb. 26, 2025): Secured the Second Circuit Panel’s unanimous affirmance of the District Court’s dismissal of claims under the Securities Act and Securities Exchange Act on behalf of a cryptocurrency company and related parties.
Republic v. Petersen and Eton Park, 23-7370(L), 23-7463, 23-7614, 23-7376(L), 23-7471, 23-7667L: Representing YPF in appeal of favorable summary judgment decision dismissing claims for roughly $16 billion in damages and pre-judgment interest arising from the Republic of Argentina’s 2012 intervention in YPF and subsequent expropriation of 51% of YPF’s capital stock.
Tiffany & Co. v. Costco Wholesale Corp.: Prevailed on behalf of Costco Wholesale Corp. before the Second Circuit in successfully overturning the lower court’s summary judgement decision that Costco counterfeited and willfully infringed on Tiffany & Co.’s TIFFANY trademark for diamond engagement rings.
Underwood v. Bank of America: Secured the Tenth Circuit’s affirmance of the district court’s grant of summary judgement in favor of Bank of America in a trademark infringement case regarding the name of a virtual financial assistant.
MidCap Business Credit, LLC v. Midcap Financial Trust: Represented Apollo Global Management and their portfolio company MidCap Financial Services in a trademark infringement lawsuit. The Debevoise team secured a dismissal at the district court level and a subsequent affirmance, in part, of the dismissal by the Second Circuit.
GrubHub Inc. v. The Kroger Co.: Secured a favorable ruling for Grubhub before the Seventh Circuit, affirming the district court’s denial of Kroger’s motion for a preliminary injunction in a trademark case involving the parties’ respective logos, both of which include a fork and a knife inside a house. Accepting many of Debevoise’s arguments, the Seventh Circuit found that the district court was well within its discretion to deny the preliminary injunction given the differences in the logos, the prominent use of the Grubhub name, and the absence of any evidence of confusion.
Appellate Experience in Criminal Cases
“The Holloway Project” Criminal Sentencing Relief: Represented clients in the Third, Sixth, Seventh, Eighth, Tenth, and Eleventh Circuits, over whether the United States Sentencing Guidelines allow courts to consider whether a nonretroactive change in law, along with other factors, can be an “extraordinary and compelling” reason for a sentence reduction under 18 U.S.C. § 3582(c)(1)(A)(i).
Shoop v. Twyford: Represented a capital habeas defendant before the Supreme Court in a case concerning the authority of a federal district court to issue an order under the All Writs Act requiring the State to transport the petitioner for medical testing in support of his claim for postconviction relief.
Partnerships with Counsel Opposing Certiorari: Advised trial counsel in various cases to obtain a denial of certiorari, including in a criminal case where the state filed a cert petition challenging the release of a juvenile offender following evidence of significant rehabilitation.
Bates v. United States: Authored a petition for a writ of certiorari on the issue of asking the Supreme Court to consider whether a district court that chooses to conduct a resentencing under Section 404 of the First Step Act is prohibited from considering a defendant’s current, legally correct Sentencing Guidelines range. Featured on the SCOTUSblog here.
United States v. McCoy, 981 F.3d 271 (4th Cir. 2020): Secured unanimous victory affirming district court’s grant of compassionate release based in part upon the First Step Act’s ending of sentence “stacking” under 18 U.S.C. § 924(c).
Carlisle v. Kentucky: Authored a petition for a writ of certiorari on the issue of whether the Fourth Amendment permits law enforcement to prolong every traffic stop by performing a criminal history check, or whether the Fourth Amendment requires a case-by-case approach that permits such checks when the government offers some evidence that the measure actually related to officer safety. Featured on the SCOTUSblog here.
Appellate Experience in Immigration Cases
Yanez-Pena v. Barr: Authored a petition for a writ of certiorari on the issue of whether “a notice to appear” as defined by 8 U.S.C. § 1229(a) and the Supreme Court’s decision in Pereira v. Sessions can consist of information compiled from multiple documents, rather than one document that contains all of the statutorily required information.
Vargas-Espejo v. Bondi: Authored a brief on behalf of a family of Colombian asylees with the Second Circuit, arguing that prior offense do not amount to “serious nonpolitical crimes” that would bar an asylum application and that the Immigration Judge’s contrary finding was arbitrary and capricious.
S v. Bondi: Assisted an asylee with their petition for review in the Second Circuit challenging the Board of Immigration Appeal’s ruling that he failed to satisfy his burden against proof for relief under the Convention Against Torture.
Amicus Briefs
Washington v. Trump on Behalf of Lawyers’ Committee for Civil Rights Under Law: Authored an amicus brief in Washington v. Trump on behalf of the Lawyers’ Committee for Civil Rights Under Law defending birthright citizenship.
Oklahoma Statewide Charter School Board v. Drummond: Authored a Supreme Court of the United States amicus brief in Oklahoma Statewide Charter School Board v. Drummond on behalf of 31 constitutional and education law scholars arguing that charter schools are in fact public schools and are employed by states to satisfy states’ obligation to provide a free public education.
United States v. Skrmetti: Authored an amicus brief in United States v. Skrmetti on behalf of the Trevor Project, Juvenile Law Center, and National Center for Youth Law opposing Tennessee’s ban on gender affirming care for transgender minors.
End Citizens United PAC v. FEC: Authored an amicus brief in End Citizens United PAC v. FEC on behalf of the Brennan Center for Justice and prominent election scholars in support of an effort to have the en banc D.C. Circuit reverse precedents ruling that courts could not review deadlocked enforcement decisions by the Federal Election Commission if the bloc of commissioners who opposed enforcement cited “prosecutorial discretion” in their reasoning.
FDA v. Alliance for Hippocratic Medicine: Authored an amicus brief in FDA v. Alliance for Hippocratic Medicine on behalf of the Nation’s leading medical societies to protect access to mifepristone.
Bradford v. Maryland: Authored a Maryland Court of Appeals amicus brief in Bradford v. Maryland on behalf of the Education Law Center, the American Federation of Teachers, the Center for Youth Law, and over thirty constitutional and educational law scholars in a long-running school funding case. The brief argued that the Maryland circuit court’s decision erroneously ignored the consensus across the country regarding the interpretation of nearly identical state constitutional provisions regarding the right to free public education.
Sittenfeld v. United States: Authored an amicus brief in Sittenfeld v. United States on behalf of twelve former federal prosecutors and officials in the Department of Justice on the application of the McCormick standard for distinguishing between legitimate political fundraising and improper exchanges amounting to campaign contribution bribery and related crimes.
Carolina Youth Action Project v. Wilson: Authored an amicus brief in Carolina Youth Action Project v. Wilson on behalf of the National Women’s Law Center and 26 civil rights and public interest organizations in support of public school students in South Carolina and the Carolina Youth Action Project, who challenged South Carolina’s “Disorderly Conduct” and the “Disturbing Schools” laws which made it illegal to use “obscene” language and act in an “obnoxious” way.
K.R. v. Duluth Public Schools Academy: Authored an amicus brief in K.R. v. Duluth Public Schools Academy on behalf of the National Women’s Law Center and a coalition of 32 public interest organizations in support of three Black and biracial children in Minnesota fighting unequal treatment and a hostile learning environment at Duluth Edison Charter Schools.
Sinclair v. San José Unified School District Board of Education: Authored an amicus brief in Sinclair v. San José Unified School District Board of Education on behalf of the National Woman’s Law Center and 21 additional advocacy organizations in support of a school board arguing that a school’s application of its nondiscrimination policy followed existing civil rights laws, which both protect against discrimination and promote inclusion of groups that have been systematically excluded.
Billard v. Charlotte Catholic High School: Authored an amicus brief in Billard v. Charlotte Catholic High School on behalf of the National Women’s Law Center and 47 additional advocacy organizations explaining that Title VII’s limited exceptions for religious employers does not allow employers to discriminate based on sexual orientation or gender identity.
Merrill v. Milligan: Authored an amicus brief in Merrill v. Milligan on behalf of the Brennan Center for Justice explaining the test for liability under Section 2 of the Voting Rights Act as established by Thornburg v. Gingles, and challenging Alabama’s assertion that Gingles unconstitutionally requires mapmakers to make race the predominant factor when drawing districts to remedy Section 2 liability.
Brown v. Pouncy: Authored an amicus brief in Brown v. Pouncy on behalf of Orleans Public Defenders challenging the one-year statute of limitations consistently applied to Section 1983 cases in Louisiana since 1989.
United States v. Idaho: Authored an amicus brief in United States v. Idaho on behalf of ten leading medical organizations, arguing that Idaho’s abortion ban directly interferes with the Emergency Medical Treatment & Active Labor Act, which ensures all patients in emergency settings receive medical treatment based on their individual health care needs.
Moore v. Harper: Authored an amicus brief in Moore v. Harper on behalf of Senator Amy Klobuchar and nineteen other United States Senators explaining that state legislatures, like Congress, are constrained by ordinary checks and balances when regulating federal elections and arguing that Congress’ role under the Elections Clause is not to replace the ordinary system of separation of powers that state constitutions establish to check state legislative overreach.
Gonzalez v. Google: Authored an amicus brief in Gonzalez v. Google on behalf of the Reporters Committee for Freedom of the Press and the Media Law Resource Center explaining how the protections provided by Section 230 of the Communications Decency Act allow for the free flow of information online that is vital to journalism. The brief argued that a proposed distinction between content recommendations and other modes of displaying third party content would erode the bright line Section 230 was intended to draw.
United States v. Palomar-Santiago: Authored an amicus brief in United States v. Palomar-Santiago on behalf of the National Association of Criminal Defense Lawyers discussing the due process concerns raised by the government’s use of removal orders in the prosecution of non-citizens for unlawful reentry under 8 U.S.C. § 1326.
Oldaker v. Giles: Authored an amicus brief in Oldaker v. Giles on behalf of the American College of Obstetricians and Gynecologists outlining how the treatment of a group of women in ICE detention constituted a violation of medical ethics and informed consent.
Citizens for Responsibility and Ethics in Washington v. FEC: Authored an amicus brief in Citizens for Responsibility and Ethics in Washington v. FEC on behalf of the Brennan Center for Justice explaining the necessity of robust judicial review to ensure the Federal Election Commission properly carries out its enforcing duties.
FBI v. Fazaga: Authored an amicus brief in FBI v. Fazaga on behalf of two cybersecurity policy experts arguing that any concern that disclosure of confidential information in camera and ex parte to a federal judge would jeopardize national security is unfounded.
Dobbs v. Jackson Women’s Health Organization: Authored an amicus brief in Dobbs v. Jackson Women’s Health Organization on behalf of international and comparative legal scholars arguing that the overturning Roe v. Wade and Planned Parenthood v. Casey would be out of step with the laws of comparable foreign jurisdictions.
United States v. Texas: Authored an amicus brief in United States v. Texas on behalf of the American College of Obstetricians and Gynecologists, the American Medical Association, and the American Academy of Pediatrics, urging the U.S. Court of Appeals for the Fifth Circuit to protect the health and well-being of Texans by affirming the district court’s injunction against the Texas Heartbeat Act.
Peltier v. Charter Day School, Inc.: Authored an amicus brief in Peltier v. Charter Day School, Inc. on behalf of the National Women’s Law Center and 56 other public interest organizations in support of three students challenging whether a school’s dress code policy constituted illegal sex discrimination in violation of the Equal Protection Clause of the U.S. Constitution, the North Carolina state constitution, Title IX of the Education Amendments Act of 1972, and North Carolina state law.
Georgiou v. United States: Authored an amicus brief in Georgiou v. United States on behalf of the Center on the Administration of Criminal Law arguing that a “due diligence” exception to prosecutors’ duty under Brady undermines defendants’ constitutional rights to due process and erodes public confidence in the system.
Ohio State University v. Redbubble: Authored an amicus brief in Ohio State University v. Redbubble on behalf of the International Trademark Association arguing against the district court’s grant of summary judgment to Redbubble on the ground that Redbubble did not “use” the Ohio State trademarks when it facilitated the sale of counterfeit Ohio State products. On appeal, the Sixth Circuit specifically cited and adopted the brief’s arguments that there were questions of fact about the extent of Redbubble’s involvement and that Redbubble could not shield its behavior by claiming to be a mere intermediary between the artists who made the counterfeit designs and the purchasers who used Redbubble’s platform to purchase those products.
LTTB v. Redbubble: Authored an amicus brief in LTTB v. Redbubble on behalf of the International Trademark Association arguing that the district court bypassed tests for aesthetic functionality in finding that Redbubble’s use of LTTB’s mark on products served merely an aesthetic purpose independent of any identifying function. The brief further explained that ornamental use can still give rise to a claim for trademark infringement.