William Welch II is an American lawyer and former high-ranking federal prosecutor who served as Chief of the Public Integrity Section of the DOJ's Criminal Division, overseeing investigations into public corruption, election crimes, and national security offenses. His career spanned over two decades, beginning as an Assistant U.S. Attorney in the District of Columbia and including a brief tenure as Interim U.S. Attorney for the District of Columbia in 2009. Welch is best known for leading several high-profile prosecutions: (1) the controversial AIPAC espionage case (United States v. Franklin, Rosen, and Weissman) in 2004, charging a Pentagon analyst and two AIPAC lobbyists with conspiracy to communicate national defense information; (2) the prosecution of former Alaska Senator Ted Stevens in 2008 on false statement charges, a conviction later vacated due to prosecutorial misconduct; and (3) the prosecution of CIA whistleblower Jeffrey Sterling in 2015 for leaking classified information. His career has been praised for tackling powerful figures but criticized for prosecutorial overreach and ethical lapses in sensitive cases.