A ballot measure in Alaska seeks to repeal the state's use of the voting method. As power in Congress hangs in the balance, all eyes will be on the two crucial states where races will be decided by a voting method that's no different than listing your top ice cream flavors.

Ranked choice voting (RCV) will be used in the congressional and state races in Maine and Alaska again this year. People in those states will have the opportunity to have their ballot count toward the person with the majority of votes, even if they strongly prefer a third party candidate.

Under RCV rules, voters rank their candidates in order of preference, first, second third, etc. If no candidate gets a majority of No. 1 rankings, votes are transferred from the candidate with the least top rankings to the other candidates based on who was ranked second, third and so on.

"The thinking is that even if my favorite candidate has no chance of winning, I can put my support and vote for someone who I also think is good," Ismar Volić, the director for the Institute for Mathematics and Democracy at Wellesley College who has been researching RCV for years, told ABC News.

Although the system has been in place in Maine since 2018 and in Alaska for the last four years, it has generated huge debates over its effectiveness and learning curve.

Opposition from elected officials has risen over the last few years, with 19 states banning the practice. Voters in Alaska will decide in a ballot question if they will join that list on Nov. 3.

Volić and other political and mathematical researchers stressed that as this debate continues across electorates, it is essential to look at the pros and cons of RCV and how it addresses the concerns from voters.

How it works Unlike standard voting, where people are mandated to choose one candidate on their ballot, RCV asks the electorate to rank the candidates in order of preference. Voters can choose to only rank one candidate on their ballot.

If one of the candidates gets more than 50% of the No. 1 rankings, they win the election. If no candidate gets more than 50%, the race goes into an instant runoff.

In that scenario, the ballots are re-examined and the candidates with the fewest No. 1 rankings are eliminated. The votes from those eliminated candidates are then transferred to the candidate that the voter ranked as No. 2 on their ballot.

If the voter did not rank more than one candidate and only chose the eliminated person, their votes are not transferred. Their ballot is still valid, however, and their vote for the eliminated candidate is still recorded.

If no candidate gets more than 50% of the vote after the elimination and vote transfer, the process restarts and continues until one candidate gets the majority.

Electorates that use the system tally the votes with computer programs. This usually happens quickly, with most tallying the runoff rounds that night.

How has RCV affected elections David McCune, a professor of mathematics at William Jewell College who has researched RCV for a decade, told ABC News that the biggest effect of the voting method is the diminishing role of a spoiler candidate.

For example, in the 2014 Maine governor's race Republican Paul LePage won with under 50% of the vote in a race among LePage, Democrat Mike Michaud and independent candidate Eliot Cutler.

With RCV, voters who choose a third-party candidate as their top choice can also rank another candidate who aligns with their views and thus ultimately help select a candidate who represents their beliefs, according to McCune. The end result is a victor who represents a bigger majority of the electorate, he said.

"The evidence points to the fact that elections become more competitive when you switch to RCV," McCune told ABC News.

David Kimball, a professor of political science at the University of Missouri at St. Louis who has studied RCV, told ABC News that candidates have also changed their campaign tactics, to shore up all of those no. 2 and no. 3 rankings.

Mudslinging and negativity end up hurting a candidate in a RCV race as it turns voters off, according to Kimball.

He pointed to the 2025 New York Democratic mayoral primary where then-State Assemblyman Zohran Mamdani and then-City Comptroller Brad Lander crossed endorsed each other and encouraged their supporters to rank the other candidate second on their ballots.

In the final round of RCV tallying, Mamdani received the majority of Lander's 120,634 transfer votes that he accumulated before he was eliminated and went on to beat former Gov. Andrew Cuomo by more than 130,000 votes, according to election data.

"It can only help your candidate if they are seeking second or third choice endorsements," Kimball said.

Volić noted that while RCV does minimize the effect of a spoiler candidate, it does not outright eliminate them. He noted the 2022 special election for Alaska's sole congressional seat where former Gov. Sarah Palin was up against Democrat Mary Peltola and Republican Nick Begich.

Palin ended up splitting the first-round votes and, even though she received more of Beich's transfer votes, Peltola edged out to surpass the 50% threshold and won the election.

"This type of spoiler event is very rare in RCV," Volić, who has analyzed data from over 1,000 RCV U.S. elections, said.

The researchers noted that Begich went on to win the seat in 2024 election, after he beat Peltola in the third round of RCV runoffs.

Volić warned that the polarization in current politics has led to more misinformation and misunderstandings about the system.

Where it's used, where it's banned As of October 2026, approximately 10.3 million voters in 14 cities and Maine and Alaska use RCV for their elections, according to data from The Ranked Choice Voting Resource Center, a non-partisan non profit that provides resources on RCV.

In this year's midterms, roughly 3.9 million voters will cast a RCV ballot for congressional, state and local elections, according to the center.

Maine voters adopted RCV for their congressional races in a state referendum in 2018, two years after a similar referendum passed for Maine's state elections. Alaska voters adopted RCV for local, state and federal races in the 2020 election.

Since Alaska made the change, however, some states have passed measures that have banned RCV. Eighteen state legislatures, including Alabama, Florida and Ohio, passed laws that banned the process between 2022 and 2026. Voters in Missouri passed a ballot measure to ban the process in 2024.

McCune said RCV's role in major elections, such as last year's New York City Democratic primary and the 2022 Alaska special election, has sparked the conversations but a lot of the details of the method are getting lost in the discussion.

"The problem is because of the polarization in politics… the pros and cons of RCV aren't being emphasized by politicians," McCune said.

RCV's fate in Alaska In 2024, a ballot initiative championed by state Republicans was given to voters asking them to repeal RCV. The measure lost by just 743 votes, or 0.24 percentage points of the total vote, according to election data.

A similar measure has been put in place for this year's election and various Republican leaders, including Begich and Alaska Gov. Mike Dunleavy, have publicly pushed for its repeal. Their calls have been amplified by President Donald Trump.

"We have the Corrupt Ranked Choice System of Voting, which shouldn’t be allowed in our Country and will, hopefully, be repealed in the November Vote," he said in an Oct. 8 social media post.

Trump claimed, without evidence, that the system is a "Democrat scam" during an Oct. 14 rally in Alaska and insinuated that it's a "way to cheat." There is no evidence in any U.S. RCV election that shows that the system benefited one party over another, according to election data compiled and analyzed by Volić and McCune.

McCune said there are examples where one candidate would have won an election through standard plurality voting with a lower percentage of the total vote, but that only because of a split ticket by an independent candidate.

"For example, in Maine you would often see one Republican, one Democrat and one independent on the ticket but the independent was close to the Democrat ideologically," he said. "In a ranked choice election, those votes for the independent would likely transfer to the Democrat. That same dynamic plays out in other places where an independent candidate was closer to Republican ideologically." The researchers said that polarization has stymied RCV research and the public's understanding, but they stressed that voters should focus on the mechanics of the system while forming an opinion.

"When you design a voting system, you want to design it to make sure it incentivizes voters to cast their true opinion," McCune said. "And you want your opinion to be supported with the facts."