Aside from whether ranked choice voting (RCV) is a good idea as policy or not, the question is sometimes raised whether it’s consistent with the U.S. Constitution. An October analysis by Jimmy Balser for the Congressional Research Service helps make clear that the answer is yes. So long as they follow other applicable provisions of the Constitution and federal law, states and cities may adopt RCV without fear of violating the federal constitution. On the other hand, courts may find RCV inconsistent with the language of at least some state constitutions, and that question has to be sorted out state by state.

In the 2011 case of Dudum v. Arntz, an ideologically diverse panel of the Ninth Circuit upheld San Francisco’s RCV law against equal protection, due process, and First Amendment challenges. It “rejected the claim that ranking candidates somehow dilutes votes,” notes Balser, “since the ability to rank preferences sequentially does not affect the ultimate weight accorded any vote cast in an election.” It likewise dismissed arguments that ranking imposes any improper burden on the right to vote. And it upheld a particular San Francisco rule according voters only three rank choices, even if more than three candidates were on the ballot, against a claim that this somehow disenfranchised voters none of whose three choices won. 

Federal courts in 2018 and 2020 also upheld Maine’s ranked choice voting law against equal protection, due process, and First Amendment challenges. In one case the court held that prescribing RCV for primary ballots did not violate the Republican Party’s First Amendment right to freedom of association. All the Maine challenges involved elections for federal office, whereas the challenges addressed by the Ninth Circuit concerned municipal elections only. 

Maine plaintiffs fared better in a state court challenge, however. In an advisory opinion, the Maine Supreme Court ruled that language in the state constitution specifying election of certain state officials by a “plurality” of votes cast in the general election implied that second-round runoffs, whether done instantly or at a later date, were not to be allowed. As a result, Maine’s RCV system does not apply to general elections for those state offices (it does apply in primaries, which are not governed by the clause in question). 

Most state supreme courts, including Alaska recently, have upheld RCV as consistent with their state constitutions, but the Maine experience stands as a reminder that each state has its own constitutional language and interpretation. In some instances, a barrier here can be overcome only by seeking an amendment to the state constitution. Those promoting RCV adoption in state and municipal elections need to make sure this issue has been researched in advance so that state and local lawmakers can be sure of acting consistently with their duty to their state constitutions.