Five strong candidates to succeed R.T. Rybak as Minneapolis mayor went through their paces at a Humphrey School debate last week. Six candidates are expected to show their stuff at a League of Women Voters forum Wednesday night.

Count me as one state political junkie who will be watching for signs that the candidates understand the strategic implications of so many serious contenders in an election that will be decided by ranked choice voting. That's the new voting method that's in place in Minneapolis and St. Paul, touted by its advocates as able to bring more civility and centrism to politics.

In Minneapolis, the mayoral contest is likely to remain well populated all the way to November. Ranked choice voting has eliminated the primary election. Come Nov. 5, the victor may well be the candidate who is most successful at snagging second- and third-place votes.

That's how Jeanne Massey of FairVote Minnesota assesses the situation. "Courting second- and even third-place votes will be the way to win," FairVote's executive director told me this week. "Just turning out your own base won't cut it."

Ranked choice voting gives voters the opportunity to rank candidates in order of preference. In a field of three or more candidates, the winner is the candidate able to amass enough first-choice votes plus second- or third-choice votes from last-place candidates to surpass the 50 percent threshhold.

Minneapolis voters approved a change to ranked choice voting in 2006, and used the system for the first time in 2009. But that wasn't a strong test. Rybak coasted to an easy victory in 2009 in a large but weak field of opponents. St. Paul Mayor Chris Coleman, who is expected to make his bid for a third term official this week, appears to occupy a similarly advantageous position in his city's ranked choice voting mayoral election this year.

But the mayoral race in Minneapolis is wide open, and chances are good that the DFL Party will fail to endorse a candidate. It should be the race to watch to assess whether ranked choice voting alters campaigning for the better, as its exponents predict.

To win second-choice votes, candidates will need to avoid harsh attacks on their rivals. They'll need to address themselves to the whole electorate, not a narrow interest group. They will have reason to campaign in all parts of the city, not just their home turf.

"Candidates can't afford to write off any voters," Massey said. "That's the beauty of ranked choice voting." If it looks as good as she predicts, legislation that stalled this year to guide other cities to adopt ranked choice voting should win the 2014 Legislature's blessing.