Citing what he sees as a void in leadership in city government and a need to see the rail project to completion, former Mayor Peter Carlisle announced Friday that he will again seek the top job at Honolulu Hale.

Carlisle, 63, will be challenging current Mayor Kirk Caldwell, who unseated Carlisle in 2012.

Who will join them remains a question. City Council Chairman Ernie Martin is acting like a candidate but said he will make a decision by the end of the month. Meanwhile, former U.S. Rep. Charles Djou said he is troubled by the escalating cost of the rail project and has not ruled out a run.

Carlisle, at a news conference, questioned Caldwell’s leadership skills.

“The incumbent has not made tough decisions, instead relying on popular sentiment to guide policies,” he said. “A leader doesn’t put his finger up to the wind and figure out which way the wind is blowing and then make a decision.”

Carlisle said seeing the rail project get off the ground was “the biggest event that occurred while I was mayor” from 2010 to 2012, and he reaffirmed his support for the city’s $6.9 billion rail project.

“Rail, while it has had many problems in terms of cost, there is no doubt that rail is the future for Honolulu, Hawaii,” he said. “It will be finished, it must be finished.”

Besides being a traffic solution, rail will offer housing and other development opportunities to Oahu neighborhoods and help ease homelessness by providing people a less expensive transportation mode, he said.

He criticized the City Council for trying to exert more influence on the Honolulu Authority for Rapid Transportation’s management of the project. Carlisle said he would reject any push to eliminate HART.

“I can’t think of anything worse than having a bunch of politicians in charge of what is now a $6.9 billion project. I think you ought to have experts. (HART CEO) Dan Grabauskas is an expert.”

The idea to stop the rail line at Middle Street is “ridiculous,” he said.

Carlisle first became mayor in 2010 after Mufi Hannemann resigned midterm in order to run for governor.

Two years later he finished third in the August 2012 special election to former Gov. Ben Cayetano and Caldwell, eliminating him from contention. In the second special election in November 2012, Caldwell defeated Cayetano.

Asked why he finished third in 2012, Carlisle said, “There was a lot of information going out there that wasn’t accurate.”

This time, he said, he will seek only one four-year term and, if elected, not run for re-election. It’s a promise he made to his wife, he said. “I do not want to have to wave signs anymore. … I don’t want to … raise funds.”

Before becoming mayor, Carlisle was city prosecutor from 1997 to 2010.

After Carlisle’s announcement Friday, Martin said he wished the former mayor good luck but had nothing to add on the subject of his own political plans.

But told of Carlisle’s comments criticizing the Council, Martin said in a text message, “Good luck in fostering an effective working relationship with the Honolulu City Council — he will need it!”

Lex Smith, Caldwell’s campaign chairman, said it will be up to voters to decide whether the incumbent has been a good mayor. “The current mayor feels he has shown leadership … by tackling the problems that have come to this city head-on and not shying away from them.”

Caldwell, Carlisle and Martin all support the rail project.

Rail critic Djou, the former congressman and onetime Council member, said in an email response to questions that he has not ruled out a run for mayor.

“I’m very concerned about the current mismanagement of the rail project,” Djou said, noting that the cost was forecast at $3.5 billion when he voted to reject it. “We need a mayor who has the courage to veto further tax increases and demand that project costs be controlled.”

Djou said he hopes other candidates do what is needed to bring the project under control. “I welcome hearing Carlisle’s detailed plans on controlling rail spending before making any decision on running,” he said.

Cayetano and University of Hawaii professor Panos Prevedouros, two other rail critics, told the Honolulu Star-Advertiser on Friday they will not run this year. Former Lt. Gov. James “Duke” Aiona said he’s inclined not to run but hasn’t made a decision.

The deadline to file is June 7.

The first special election for the nonpartisan mayor’s race is held in conjunction with the Aug. 13 primary election. If the first-place finisher gets more than 50 percent of the votes cast, he or she is declared the winner. Otherwise, the two top finishers go head to head in the second special election on Nov. 2, general election day.

Caldwell filed nomination papers last week. Five others had done so as of 4:30 p.m. Friday: Kurtleigh Baker, Lawrence Friedman, Timothy Garry, Angela Kaaihue and Joseph Wargo.