Hashim Mooppan focuses on appellate advocacy and dispositive motions practice. A former clerk to Supreme Court Justice Antonin Scalia, Hashim primarily litigates cases raising complex questions of federal law.

Recently, Hashim successfully argued in the D.C. Circuit in a constitutional challenge to the 2006 Congressional reauthorization of Section 5 of the Voting Rights Act. In an opinion that quoted extensively from the appellate brief that Hashim primarily authored, the D.C. Circuit held that private parties can have standing and a cause of action to challenge Section 5. It thus reversed the district court's dismissal of the suit that Jones Day had brought on behalf of several individuals from Kinston, North Carolina, who were injured when Section 5 suspended a local nonpartisan elections referendum that they supported and benefited from.

Among the other cutting-edge and high-profile matters in which Hashim has been heavily involved are an enumerated-powers challenge to the individual health insurance mandate in the Patient Protection and Affordable Care Act, a First Amendment challenge to the Family Smoking Prevention and Tobacco Control Act, and a separation-of-powers challenge to the Public Company Accounting Oversight Board. In addition, Hashim has helped develop and implement the legal strategy employed by R.J. Reynolds Tobacco Company in defending against parallel litigation by the attorneys general of nine states under the Master Settlement Agreement. He also has coauthored briefs successfully defending a $356 million "Winstar" judgment against the United States and successfully attacking an unprecedented injunction under the Robinson-Patman Act.