PORTLAND, Maine — “Confusion” was a watchword of the 2011 Portland mayoral race.

A field of 15 candidates battled for votes — and if not the first pick, they asked to be second or third or fourth. As city voters elected a mayor with ranked-choice voting, being checked as a lower choice on the ballot still could help win the race as candidates with fewer votes peeled away.

With three candidates on the ballot this year, the dynamics of the race are entirely different, despite the two leading candidates being the same as in 2011. The smaller ballot raises new questions for the relatively new mayoral post and the city’s ranked-choice voting system.

Will more campaigning turn negative? Portland held its first citywide mayoral election in 88 years in 2011. There was no popularly elected incumbent or record that candidates really were running against.

That’s all changed in 2015, as reflected by an early salvo this month from city councilors and school board members who while endorsing challenger Ethan Strimling also chided Mayor Michael Brennan.

Brennan, seeking re-election to another four-year term, responded by defending his work on education and the economy.

As we know, it’s not just the direct actions of candidates or incumbents that influence voting but also events or changes in the city that perhaps had little to do with the mayoral position Brennan himself has said holds little direct power over day-to-day city operations.

The small size of this year’s candidate field also ramps up the likelihood that candidates specifically could target others, as the ballot at this stage looks more like a traditional election with two front-runners and one long-shot candidate.

What will be the power of the endorsement? It’s hard to gauge the influence of an endorsement, but criticism of Brennan from past mayoral contender Nick Mavodones allows for some analysis based on the 2011 results. (The impact of Brennan’s endorsement by the Longshoremen’s union, by contrast, is a little bit harder to gauge.)

In 2011, Mavodones had amassed 23 percent of the vote in the second-to-last round of runoff voting. Of those voters, 1,456 ranked Brennan as their next choice; 1,204 picked Strimling next. And another 1,415 didn’t put anyone after Mavodones.

That’s a sizeable chunk of voters out of the 16,109 votes still in play by the time a winner was chosen.

[tableau server=”public.tableau.com” workbook=”Portlandmayoralelectionresults” view=”Theraceinachart?:showVizHome=no” tabs=”no” toolbar=”yes” revert=”” refresh=”” linktarget=”” width=”560px” height=”487px”][/tableau]

If Strimling received all the Mavodones voters and a handful of those who didn’t pick anyone after Mavodones, it would have put him ahead in 2011. So, whether those voters this time will turn out to check “Strimling” could make a big difference in the first round of voting.

[tableau server=”public.tableau.com” workbook=”Portlandmayoralelectionresults” view=”Gainsinpies?:showVizHome=no” tabs=”no” toolbar=”yes” revert=”” refresh=”” linktarget=”” width=”475px” height=”387px”][/tableau]

That first round will be more important this time around. While the relative position of the candidates didn’t change too much through early rounds of instant runoff voting in 2011, vote totals rose in the range of 75 percent for Brennan and Strimling by the final round.

Brennan in 2011 gained nearly double the amount Strimling earned from voters who picked Green Party candidate David Marshall one spot higher.

[tableau server=”public.tableau.com” workbook=”Portlandmayoralelectionresults” view=”Gainsbyround?:showVizHome=no” tabs=”no” toolbar=”yes” revert=”” refresh=”” linktarget=”” width=”560px” height=”437px”][/tableau]

In 2011, Brennan and Strimling combined won about 43 percent of the first-choice votes, with the remainder shared among 13 candidates with sizeable first-choice followings and those lesser known.

If the numbers hold from initial polls — with Strimling and Brennan with a vote share at least 10 times larger than possible contenders Christopher Vail and Tom MacMillan — those subsequent rounds of vote sifting will be much less interesting, depending on how far apart Brennan and Strimling are after the first round.

Vail, according to city records, did not qualify for the ballot.

Early polling from the Maine People’s Alliance-affiliated Maine People’s Resource Center, which was very accurate on first-round picks in 2011, shows an estimated 26.4 percent of voters are still undecided.

The early polling shows a tough hill for Brennan to climb but entirely leaves open the possibility that the race could be close. If that’s the case, the 6.2 percent of voters the poll shows as now leaning toward MacMillan or Vail could be the deciding factor.

Will issues make center stage, or will style lead the discussion? Both of the leading candidates have served as Democratic legislators and so far have not set out any specific differences in platforms, but their public-facing campaigns are young.

In early hints of likely campaign themes, Brennan has highlighted his connections to residents of Portland’s various neighborhoods. The Longshoremen’s union endorsement reinforces Brennan’s “man of the people” persona.

Meanwhile, Strimling and his supporters have emphasized what they see as his greater ability to bring people of diverse backgrounds together to collaborate in search of solutions.

The criticism of Brennan from some city councilors last week focused on style, leadership skills and communication. That level of personal conflict matters to the city councilors supporting Strimling. But will that criticism matter to voters?

How will the city’s story itself play into voters’ minds? Portland had changed a lot since 2011 for reasons tied to city government and for reasons outside of its control.

Development, economic gains and other generally positive perceptions about the city could factor into voters’ decisions in the polling booth.

If the candidates don’t stake out differences on specific programs or functions of government, broad changes in the city since 2011 and how those changes are spun — what’s the good news and what’s the bad news? — likely will become part of the discussion.

At the state and federal levels, incumbency remains a huge asset. But familiar candidates, ranked-choice voting and the absence of outside support from party regulars add variables that alter that equation. Watching how Brennan’s and Strimling’s campaigns adapt strategies in response to those variables will keep Maine’s political class well occupied through Nov. 3.

Darren is a Portland-based reporter for the Bangor Daily News writing about the Maine economy and business. He's interested in putting economic data in context and finding the stories behind the numbers.