The idea is catching on that instant runoff voting -- that is, ranking candidates in order of preference -- would change Minnesota democracy for the better. Last year, it was embraced by voters in Minneapolis, for implementation in city elections perhaps as soon as 2009.

This year, St. Paul voters should get a chance to join the experiment. A petition drive appears likely to collect more than the 5,098 signatures required to put a switch to instant runoff voting on this year's City Council election ballot.

If this political year is like most others in St. Paul, turnout at the city's primary election on Sept. 11 will help the Better Ballot Campaign make its case for change. Typically, fewer than 15 percent of registered city voters turn out for the primary in a nonmayoral year such as this one.

If city elections employed the instant runoff method, the September city primary and its feeble expression of popular will would no longer be necessary. Voters would troop to the polls just once, on the customary Tuesday in November, and would rank candidates by number. Ballots would be counted, the low vote-getter eliminated. Then the ballots would be recounted; those whose first-choice candidate had been eliminated would be counted as votes for the second-choice candidate.

That exercise would be repeated as many times as needed, until one candidate topped the 50 percent-plus-one majority threshold.

Critics contend that instant runoff voting violates the constitutional principle of one person, one vote. That's a misunderstanding. Under instant runoff voting, every ballot cast is counted the same number of times.

The efficiency and cost savings associated with eliminating the September primary are the most obvious advantages of instant runoff voting. But there likely would be other, more subtle ones.

The tone of campaigns would likely change for the better if candidates were angling to be not only the first choice of their own backers, but also the second choice of someone else's. The willingness of voters to back new candidates would likely increase if those voters could also redirect their votes to their second choices. Wider political diversity ought to be the result.

While St. Paul voters learn more about instant runoff voting before this fall's city election, a task force established by Secretary of State Mark Ritchie is examining its potential application to state and other local elections. He told a conference at Hamline University on Tuesday that the state's overseas-based military personnel in particular would benefit from the one-ballot, one-deadline convenience this voting method offers.

The 2008 Legislature should consider giving that special group of voters the first chance to experience instant runoff voting's advantages in a state election.