Some on the Right Flirt With a Voting Method the Left Loves

Long viewed as an intriguing, if somewhat wonky, approach to conducting elections, ranked-choice voting — allowing voters to list candidates in order of preference instead of selecting just one — appears to be having a moment.

Across the country, voters have adopted the system for municipal and county elections in each of the last 27 times the issue has been put to them. Nevada and Oregon — and perhaps Colorado and Idaho as well — will hold referendums on adopting the system this fall. Maine and Alaska already have adopted it.

Proponents say ranked choice reduces polarization by forcing candidates to seek broad support, and that it allows voters to support minor or protest candidates without them becoming spoilers. Critics call the system confusing and even undemocratic, since candidates who initially get the most first-place votes don’t always win in the end.

But just how popular ranked-choice voting is may depend on the group that has most often waged tooth-and-claw battles against it: conservatives, and in particular Republican political figures, who have ideological and practical reasons to oppose the system.

The Republican National Committee urged Congress and the states a year ago to oppose ranked-choice voting “in every locality and level of government.” Republican-run legislatures in Kansas and Georgia are considering bills to outlaw it. When a coalition of advocacy groups began mobilizing last year to place a ranked-choice initiative on the ballot in Idaho, the G.O.P. supermajority in the Legislature preemptively banned it.

At least a few Republicans say they see cracks in that opposition. Whether they’re right could determine if ranked-choice voting, also known as instant runoffs, could have a future beyond largely Democratic states and municipalities.