Tuesday is primary election day in Duluth, and if voters there follow this year's pattern in other Minnesota municipal primaries, most won't cast a ballot. Turnout was abysmal on Aug. 11 in St. Louis Park (3.6 percent in a mayoral primary), Bloomington (4.9 percent in City Council District 2) and Maplewood (16 percent in a five-way contest for council member at large).

We hope Duluthians are true to their reputations for civic engagement and troop to the polls in substantially higher numbers than their suburban counterparts did. But we also urge them to consider whether Minnesota's port city ought to follow the lead of Minneapolis and St. Paul and eliminate its primary altogether. That's what ranked-choice voting (RCV) does — and that's what Duluth voters have a chance to adopt in the Nov. 3 general election.

RCV is also known as instant-runoff voting, because it does away with the need for a primary. That was a prime reason — but not the only one — for voters in Minneapolis in 2006 and St. Paul in 2009 to amend their city charters to employ RCV in municipal elections.

The experience in those cities since then has been positive enough to invite other municipalities and, potentially, the state of Minnesota to follow their lead. Yes, ballots in which voters rank their preferences among multiple candidates require extra time to tabulate — though ballot-counting software is steadily improving and should produce speedier results in future years. Yes, Minneapolis voters were confronted with a very long ballot in 2013, when its mayoral seat was open — as is the case in Duluth this year. But RCV was not chiefly to blame for a 35-candidate mayoral field in Minneapolis; a laughably low $20 filing fee was. That has since been raised to $500.

But predictions that the new voting method would confuse voters, or would be unworkable in situations in which multiple candidates are elected to the same office, were not borne out. In 2013, a poll by the advocacy group FairVote Minnesota found that 85 percent of Minneapolis voters considered ranking their preferences 1-2-3 either very or somewhat simple to use.

Despite that track record, Duluth voters are hearing those same negative predictions from several quarters, most notably the local Central Labor Body, which announced its opposition last month. Its leaders cite one thing more: They fear that in contests that produce more than one winner — such as this year's two at-large seats on the Duluth City Council — RCV would diminish chances that two labor-supported candidates would win.

That's typical of the resistance RCV has met elsewhere from interest groups that exert considerable sway in today's plurality-rule elections. They are loath to change a system that is serving them well. What voters must ask is whether democracy is well-served by the status quo.

To date, RCV in Minneapolis and St. Paul has lived up to its more positive claims. It's credited with more campaign civility, as candidates seek to become the second choices of voters who support their opponents. It has diminished candidates' use of negative advertising and, consequently, allowed for lower-cost campaigns and less special-interest influence. Best of all, in a multicandidate field it has elected the candidate with the broadest electoral support, via a single election with substantial turnout.

That gives the ultimate winner more democratic legitimacy than a low-turnout primary can — and that's something Duluth voters should want for their elected officials.