On May 20th, the Ninth Circuit Court of Appeals unanimously upheld a lower federal court ruling rejecting a legal challenge to the City of San Francisco's use of ranked choice voting (RCV, also known as instant runoff voting, or IRV). The three-judge panel emphatically dismissed the plaintiffs' arguments, including a particularly clear rejection of the claim that RCV violates the principles of one-person, one-vote or equal protection under the law.