Update: Ballot Question 1 has been approved — New York City will adopt ranked-choice voting.

New York City voters will head to the polls on Tuesday to decide something that will have a big impact on future elections: how they vote.

The city, which is the most populous in the country, is the latest to weigh whether it should take up ranked-choice voting for local elections, an option that’s being floated as part of Ballot Question 1. If ranked-choice voting were to go into effect, voters would rank their top five candidates in order of preference, rather than simply picking one candidate.

The ballot measure is expected to be approved and would be implemented for the first time in 2021 during elections for roles such as mayor and city council. Should the measure pass, ranked-choice voting would be used only in regional primary races, and not the general election.

Polls close at 9 pm ET. Live results, powered by Decision Desk, are below.

How New York City’s ranked-choice voting initiative works

Advocates of ranked-choice voting argue it is an electoral reform with many benefits.

Because a voter is asked to evaluate multiple candidates, it pushes politicians to do outreach to a larger group of constituents. Additionally, it’s led to the election of more women and more diverse lawmakers in several of the places it’s been implemented. Proponents also argue that the system results in the election of candidates favored by the greatest number of people, and is therefore more democratic than other systems.

Twenty cities and multiple states have already adopted ranked-choice voting for various races, including Maine, which has begun using this method for federal elections.

As Lee Drutman writes for Vox, it works like this:

As the name suggests, ranked-choice voting lets voters mark their first-choice candidate first, their second-choice candidate second, their third-choice candidate third, and so on. Each voter has only one vote but can indicate their backup choices: If one candidate has an outright majority of first-place rankings, that candidate wins, just like a traditional election. But if no candidate has a majority in the first round, the candidate in last place is eliminated. Voters who had ranked that candidate first have their votes transferred to the candidate they ranked second. This process continues until a single candidate gathers a majority.

Were New York City to take up ranked-choice voting, it would be a significant step for the electoral reform movement, and even more cities might consider following a similar path.