The Federal Election Commission (FEC) (defendant) determined that the American Israel Public Affairs Committee (AIPAC) was not a “political committee” and thus did not have to disclose its members, contributions, and expenditures, as was required of political committees. A group of voters (plaintiffs) appealed the FEC’s decision based on the Federal Election Campaign Act (Act), which stated that “[a]ny person who believes a violation this Act . . . has occurred, may file a complaint with the [FEC]” and that “[a]ny party aggrieved by an order of the [FEC] dismissing a complaint filed by such party . . . may file a petition” in district court. The court of appeals reversed the FEC decision. The FEC appealed, claiming that the plaintiffs lacked prudential standing to bring the suit. The United States Supreme Court granted certiorari.