“Coming out of a primary, you end up having a nominee who has more support, and the primary itself probably hasn’t been as vicious and bitter as you might have seen otherwise,” he said.

FairVote also says ranked-choice voting can increase turnout, open up the political playing field and mitigate the power of money in politics.

Vicki Hiatt, the chairwoman of the Kansas Democratic Party, said she expected higher turnout in this year’s presidential primary in the state. She added that people were happy they would be able to cast their ballot without strategizing about electability.

“Sometimes they’re voting for the lesser of two evils,” she said. “So most people have said to me: ‘This is great. Now I can vote for who I really want.’”

Critics of ranked choice say it can upend electoral politics in unpredictable ways, cost money or dampen turnout. And in some states and cities where ranked choice has come up for a vote, opponents argued that the cause was supported by dark money or other outside funding.

In 2018, Paul LePage, a Republican governor of Maine who had won two terms in office without a majority, called ranked-choice voting “the most horrific thing in the world” and questioned its constitutionality. Republicans in Maine are still fighting it today.

And in New York in November, members of the N.A.A.C.P. and the City Council’s Black, Latino and Asian Caucus spoke out against ranked-choice voting. They were partly worried that it could hurt candidates of color, and that a more complicated ballot could reduce turnout.