Mithun Mansinghani is an experienced appellate and trial litigator who has argued cases at all levels in state and federal court, including at the U.S. Supreme Court. Mr. Mansinghani has argued more cases before the Justices of the Oklahoma Supreme Court than any other litigator in the last decade.
From 2017 to 2022, Mr. Mansinghani served as Oklahoma Solicitor General, the state’s chief advocate on appellate matters, constitutional issues, and challenges to federal regulation. In that role, he also advised the Attorney General, the Governor, the Legislature, and other state leadership on critical and high-stakes legal issues.
As the state’s Solicitor General, Mr. Mansinghani has been nationally recognized for amici briefs he authored on behalf of multi-state coalitions at the U.S. Supreme Court. These amici briefs have been cited in Supreme Court opinions, referenced by the Justices at argument, and received a National Association of Attorneys General “Best Brief” award. He also provides commentary on U.S. Supreme Court cases for media outlets including NPR, The New York Times, SCOTUSblog, and Bloomberg.
In addition to appellate litigation, Mr. Mansinghani has first-chaired several bench trials to successful verdicts. He has conducted all stages of district court litigation, and has prevailed in numerous cases on summary judgment and motions to dismiss.
Mr. Mansinghani’s extensive experience includes federal and state constitutional law, litigating federal and state regulation, and work with state attorneys general. He also has significant experience negotiating with Native American tribes and has litigated some of the nation’s most important federal Indian law cases.
Prior to serving in the Oklahoma Attorney General’s Office, Mr. Mansinghani was a litigator with Gibson, Dunn and Crutcher in Washington, D.C. He served as a law clerk to the Hon. Jerry E. Smith on the U.S. Court of Appeals for the Fifth Circuit. Mr. Mansinghani graduated with honors from Harvard Law School, where he served as an editor of The Harvard Law Review.
Court Admissions
Oklahoma Bar
Texas Bar
District of Columbia Bar
Supreme Court of the United States
United States Court of Appeals for the Second, Fourth, Fifth, Sixth, Seventh, Tenth, Eleventh, and District of Columbia Circuits
United States District Courts for the Western, Northern, and Eastern Districts of Oklahoma
United States District Court for the District of Columbia
Representative Experience
Federal and State Regulatory
Successfully argued case challenging the validity of FCC Order capping rates that jails and prisons may charge to inmates for intrastate phone calls, convincing the court in 2-1 decision that the regulation was in excess of statutory authority and arbitrary and capricious. Global Tel*Link v. FCC, 859 F.3d 39 (D.C. Cir. 2017).
Successfully argued as Intervenor in appeal of earlier victory on summary judgment upholding first-in-the-nation EPA approval of state permitting program for disposal of coal combustion residuals. Waterkeeper Alliance v. Regan, 41 F.4th 654 (D.C. Cir. 2022); Waterkeeper Alliance v. Wheeler, 330 F.R.D. 1 (D.D.C. 2018).
Argued case challenging the legality of the EPA’s and the Army Corps’ rule defining the scope of the Waters of the United States (WOTUS) for the purposes of the Clean Water Act, urging jurisdictional rule that was eventually adopted by the U.S. Supreme Court. Chamber of Commerce & State of Oklahoma v. EPA, et. al., No. 15-5038 (10th Cir.).
Successfully removed case to federal court and prevailed on summary judgment in defense against an equal protection challenge to referendum that amended the Oklahoma Constitution’s alcohol regulation. Retail Liquor Ass’n of Okla. v. Okla. Alcoholic Beverage Laws Enforcement Comm’n, 276 F. Supp. 3d 1230 (W.D. Okla. 2017).
Prevailed in appeal alleging that stock exchanges had improperly charged fees to certain market participants. Citadel Securities, LLC v. Chicago Bd. of Options Exchange, 808 F.3d 694 (7th Cir. 2015).
Represented financial industry groups in challenge to CFTC policy statement on international swap transactions and related regulations, convincing the court that the CFTC had failed to consider costs and benefits in eight separate rulemakings. Securities Industry and Financial Markets Association v. CFTC, 67 F. Supp. 3d 373 (2014).
Successfully defended state withdrawal from federal pandemic unemployment benefit programs, obtaining emergency stay of lower court injunction. Owens v. Zumwalt, 2022 OK 14.
Co-authored amicus brief convincing Oklahoma Supreme Court that exclusive remedy provision of Oklahoma’s Administrative Workers’ Compensation Act did not immunize stockholders of an employer from third-party liability in suit by an injured employee, unless the stockholders are acting in the role of employer. Odom v. Penske Truck Leasing Co., 2018 OK 23.
Successfully persuaded Oklahoma Supreme Court to adopt an interpretation of a statute capping the maintenance fee for interlock devices installed in the vehicles of convicted drunk drivers. Heath v. Guardian Interlock Network, Inc., 2016 OK 18.
Successfully defended on appeal judgment upholding the constitutionality of state law that permits patients to visit a physical therapist for up to 30 days without referral from a physician. Oklahoma Osteopathic Ass’n v. Fallin, No. 115,423 (Okla. Civ. App.).
Successfully defended Oklahoma’s first-ever medical marijuana regulations. Gregg v. Oklahoma, No. CV-2018-1416 (Cleveland Cnty.).
Prevailed in challenge to new state law allowing adults to carry firearms without the need to obtain a permit. Lowe v. Stitt, No. CJ-2019-5628 (Okla. Cnty.).
Indian Law
Prevailed in landmark U.S. Supreme Court case confirming state sovereignty within state borders and holding states have jurisdiction over non-Indians who commit crimes against Indians. Oklahoma v. Castro-Huerta, 142 S. Ct. 2486 (2022).
Obtained certiorari and argued case at U.S. Supreme Court challenging lower court decision holding that the reservation of the Muscogee (Creek) Nation had never been disestablished. McGirt v. Oklahoma, 140 S. Ct. 2452 (2020) and Sharp v. Murphy, 140 S. Ct. 2412 (2020).
Successfully argued in challenge by Oklahoma’s Legislature to the Governor’s approval of state-tribal gaming compacts with two Indian tribes, defending an earlier-authored Attorney General opinion that the Governor lacked authority to enter into those compacts under state law. Treat v. Stitt, 2020 OK 64.
Obtained extraordinary stay pending certiorari from U.S. Supreme Court in case seeking to overturn long-held assumption that states lack jurisdiction over non-Indians who commit crimes against Indians in Indian country and challenging lower court decision refusing to apply procedural bars to postconviction claims challenging state court jurisdiction. Oklahoma v. Bosse, 141 S. Ct. 2696 (2021).
Prevailed against multi-million dollar claim by Native American tribe that State had violated state-tribal gaming compacts. Wichita and Affiliated Tribes v. Stitt, No. 19-cv-1198 (W.D. Okla.).
Successfully negotiated water rights agreement between federal, state, local, and tribal governments.
Federal and State Constitutional Law
Successfully defended major Eighth Amendment challenge to Oklahoma’s lethal injection protocol at the U.S. Supreme Court. Glossip v. Gross, 135 S. Ct. 2726 (2015).
Prevailed in defense of the constitutionality of a law that restricts admissible evidence of medical expenses to those expenses a plaintiff has actually paid or is still liable to pay, rather than expenses initially billed by a healthcare provider. Lee v. Bueno, 2016 OK 97.
Successfully defended validity of pension reform statute, arguing that the Legislature’s alleged failure to comply with a statute creating legislative procedures for passing future laws affecting retirement systems was a nonjusticiable question. Stevens v. Fox, 2016 OK 106.
Argued at the Oklahoma Supreme Court in successful defense of the constitutionality of a workers’ compensation law requiring use of the Sixth Edition of the American Medical Association’s Guides to the Evaluation of Permanent Impairment for expert medical testimony in evaluating permanent partial disability. Hill v. Am. Medical Response, 2018 OK 57.
Prevailed as first chair in six-day bench trial on challenge to state’s legal injection protocol, after having successfully defeated several motions for preliminary injunction following evidentiary hearings, successfully moved for partial dismissal and partial summary judgment, and prevailed in numerous appeals to the Tenth Circuit and U.S. Supreme Court. Glossip v. Chandler, No. 14-CV-665 (W.D. Okla.).
Secured reversal after petitioning for certiorari asking the Oklahoma Supreme Court to review a decision of the Court of Civil Appeals finding that the plaintiff had established that her religious exercise had been “substantially burdened” under the Oklahoma Religious Freedom Act by the Department of Public Safety’s requirement that her driver’s license contain a high-resolution photograph of her. Beach v. Okla. Dep’t of Public Safety, 2017 OK 40.
Convinced the Oklahoma Supreme Court to hold that, contrary to earlier precedent, state agencies, boards, and commissions have the power to address constitutional issues brought before them. Robinson v. Fairview Fellowship Home for Senior Citizens, Inc., 2016 OK 42.
Prevailed in defense of the constitutionality of state budget bills appropriating billions of dollars in suit alleging various state constitutional infirmities. Reynolds v. Fallin, 2016 OK 38.
Successfully defended on appeal the constitutionality of Oklahoma’s unclaimed property system against state constitutional claims and claims of violations of the federal Takings and Due Process clauses. Dani v. Miller, 2016 OK 35.
Amicus Briefs
Filed an amici brief cited by the U.S. Supreme Court in the majority opinion by the Chief Justice, as well as in a concurrence by Justice Alito, in a case upholding a Montana school voucher program. The brief was filed on behalf of 18 states and won a “Best Brief” award from the National Association of Attorneys General. Espinoza v. Montana Dep’t of Revenue, 140 S. Ct. 2246 (2020).
Led brief on behalf of 17 states in support of decision to add citizenship question to the 2020 Census, which was cited at oral argument by Justice Gorsuch. Department of Commerce v. New York, 139 S. Ct. 2551 (2019).
Filed amici brief on behalf of eleven states supporting farms in successful challenge to California union regulation requiring union organizers to be allowed to enter farms as an uncompensated per se taking. Cedar Point Nursery v. Hassid, 141 S. Ct. 2063 (2021).
Led 19-state amici brief in challenge to race-based admissions policies in higher education, presenting data from universities in states that have mandated race-neutral admissions. Students for Fair Admissions v. Harvard, No. 20-1199 (S. Ct.); Students for Fair Admissions v. University of North Carolina, No. 21-707 (S. Ct.).
Submitted 17-state amici brief presenting comprehensive data and arguments showing states are reasonable in conducting stops of vehicles registered to drivers whose licenses have been suspended or revoked. Kansas v. Glover, 140 S. Ct. 1183 (2020).
Filed multi-state amici brief arguing that the Hobbs Act does not prevent courts from disagreeing with FCC interpretation of the Telephone Consumer Protection Act. PDR Network, LLC v. Carlton & Harris Chiropractic, Inc., 139 S. Ct. 2051 (2019).
Filed amicus brief successfully supporting Colorado, joined by all other Tenth Circuit states, urging reversal of district court decision holding that sex offender registration requirements were unconstitutional as applied to the plaintiffs under the Eighth and Fourteenth Amendments. Millard v. Camper, 971 F.3d 1174 (10th Cir. 2020).
Filed amici brief on behalf of 20 states successfully supporting U.S. House Chaplain’s decision to decline to allow atheist activist to give a secular statement in lieu of legislative prayer. Barker v. Conroy, 921 F.3d 1118 (D.C. Cir. 2019).
Elections and Initiative Petitions
Prevailed as first-chair in consolidated preliminary injunction hearing and trial on merits in defense of state’s absentee ballot laws in advance of the 2020 general election. DCCC v. Ziriax, 487 F. Supp. 3d 1207 (N.D. Okla. 2020).
Prevailed in challenge to initiative petition seeking to repeal state’s new permitless carry of firearms law, with the Oklahoma Supreme Court agreeing that the petition contained a misleading gist. In re Initiative Petition No. 425, State Question No. 809, 2020 OK 58.
Prevailed in defense of state law requiring initiative petition signatures to be collected during a 90-day circulation period after the law was challenged as unconstitutional as applied during the COVID-19 pandemic. Kiesel v. Rogers, 2020 OK 65.
Successfully persuaded the Oklahoma Supreme Court to abstain from addressing pre-enactment challenges to legislative referendums in a case challenging the constitutionality of a proposed amendment to the Oklahoma Constitution to recognize a fundamental right to engage in farming and ranching activities. Save the Illinois River, Inc. v. State of Oklahoma, 2016 OK 86.
Successfully defended First Amendment challenge in an original action at the Oklahoma Supreme Court to a State election law requiring candidates to be registered with a party for at least six months prior to filing for candidacy. Setzer v. State Election Board, No. 114,961.
Arbitration
Argued case successfully vacating an arbitration award prohibiting the State from collecting sales tax on a tribe’s retail sale of goods, convincing the court that the arbitration clause was legally invalid under the Federal Arbitration Act. Citizen Potawatomi Nation v. Oklahoma, 881 F.3d 1226 (10th Cir. 2018)
Tax
Argued at the Oklahoma Supreme Court in successful defense against a challenge to the State’s reduction of a sales tax exemption for motor vehicle sales, persuading the Court that such a change was not a “revenue bill” that must comply with the procedures of Article V, § 33 of the Oklahoma Constitution. Oklahoma Automobile Dealers Association v. State, 2017 OK 64.
Prevailed at the Oklahoma Supreme Court in defense of a bill that modified state earned income tax credit to make it nonrefundable, arguing that it was not a “revenue bill” subject to the legislative procedural requirements of Article V, § 33 of the Oklahoma Constitution. Ali v. Fallin, 2017 OK 39
Oil and Gas
Co-authored amicus brief in defense of constitutionality of a state statute that specified that owners or operators of oil or gas wells are deemed to be the employer of an employee for the purposes of the exclusive remedy provision of the Administrative Workers’ Compensation Act. Strickland v. Stephens Production Company, 2018 OK 6.
Education
J.D., Harvard Law School, 2011, cum laude
Supervising Editor, Harvard Law Review
B.A., Political Science and Policy Studies, Rice University, 2008, magna cum laude