This November, Portland is undertaking a type of voting never tried in Maine before. Its next mayor will be chosen by a process by which voters rank their choices in the order of preference. But that could be quite the task for both the voters and the city officials preparing for the election, given a crowded field of candidates. It now stands at 19 with former state senator Ethan Strimling announcing his bid for mayor today.

"I'm going to go out and try to get every first place vote that I can, and if somebody has another choice for first but they think I would be a good second choice if their's doesn't win, that's great," Strimling says.

With a vigilant eye on the growing roster of candidates, the city is planning voter education workshops with the League of Women Voters ahead of the Nov. 8 election. And it's prepared to sign a contract this week with a DC-based election balloting company called True Ballot, which has experience with ranked-choice voting.

"We want to identify any of the possible pitfalls and avoid any kind of voter confusion on the day of the election," says city spokeswoman Nicole Clegg. Clegg says that if someone gets a simple majority of first choice votes--that'd be 50 percent plus 1 vote--the person wins.

"However, given the number of candidates and the possibility that the vote could be widespread among a lot of different people, we'll have this company come in the next day and they'll scan all the ballots and then they'll start by discounting the candidates with the least amount of votes," Clegg says.

Then the second choices of that candidate's supporters are added to the first-choice tallies for the remaining candidates. If no winner emerges, then the process is repeated until one person has a majority. Sometimes this process is called instant run-off voting.

Michael Franz, associate professor of government at Bowdoin College, says it's not surprising that so many people have thrown their hats into the ring.

"Anyone who's interested in this kind of thing, or has something to offer, perhaps, may think they can benefit from the ranked-choice voting in such a way that they could become a player in any second-round calculation. So I can see how people would say, 'Well, I'm definitely going to try it because it gives me more opportunities.'"

But Franz says that having a long roster of candidates means more work for voters. "When you have 19 candidates and all sorts of different proposals and a lot of issues to consider, you have to a lot of self-education and that can be time-consuming, and that could be a downside for people," he says.

Some cities with ranked-choice voting, such as San Francisco, require voters to pick their top three choices. Portland allows people to rank as many or as few candidates as they want. Francis Neely, associate professor of political science at San Francisco State University, says the more candidates there are, the more mistakes are made.

"Some people make a mistake by marking more than one candidate in one column, which means they're ranking more than one person first, and of course there's no way to know which one they really meant to be first, so they have to disqualify that ballot," Neely says.

This is an issue facing San Francisco, where Neely says there are about 30 people running for mayor so far.

In Portland, there is still time for more candidates to jump in. Many of the candidates may be familiar to voters, such as former state senator Michael Brennan, former state Rep. John Eder and city councilors Jill Duson, David Marshall and Nick Mavodones, who is currently mayor. Mavodones, was picked by fellow councilors under a decades-old process that voters overturned at the polls last year.

But the majority of candidates have not served in elected office: They include marketing consultant Jodie Lapchick, one of two women in the race, Somali businessman Hamza Haadoow and Jed Rathband, the political consultant who was hired by various business groups to campaign for an elected mayor system last year.

What also could happen is the number of candidates actually dwindles. At least two candidates have had run-ins with the law that might make it hard for them to get the support they need. Candidates need to submit at least 300 valid signatures on their nomination papers by Aug. 29 to get on the ballot.

See the entire list of candidates running in Portland's mayoral election.