The tenor of this year’s Honolulu mayoral campaign turned up a notch last week when candidates at a televised forum began talking, and in some cases finger­-pointing, about the city’s troubled $9.2 billion rail project.

Thursday night’s hourlong forum on the weekly panel show “Insights on PBS Hawai‘i” was held via teleconference using Zoom technology.

The long-running show traditionally has been done in a conversational style without structured time limits, a format that provided candidates the chance to interrupt and talk over each other. Moderator Yunji de Nies, meanwhile, did not have the technology to “mute” any of the candidates.

The forum was the first this campaign season to be broadcast over traditional television airwaves and the first to include former Mayor Mufi Hannemann, who headed the city when rail construction first began.

Speaking first, Hannemann defended his role with the project while several of his opponents blamed him for the jump in its costs to an estimated price tag of $9.2 billion from $5.3 billion.

Hannemann, who was the first to respond to the rail question, said his administration moved forward with the rail project after Oahu voters, the state Legislature and the City Council approved it.

“When I left City Hall, rail was a little bit under $5 billion,” Hannemann said. “Now, something happened between $5 billion and $9 billion in those 10 years I was out of office. So obviously, there’s been some managerial questions there, some oversight questions there.”

Without naming them, Hannemann pointed out that Councilwoman Kym Pine voted to give approvals to advance the project and that former U.S. Rep. Colleen Hanabusa was chairwoman of the HART board “when some of those cost increases exploded.”

The project can’t be halted because it would cost billions to tear it down, he said. “We have to figure out a way to push it through.”

Hanabusa, however, said Hannemann has “forgotten a lot of things.” Recent state and city audits as well as a federal investigation into rail financing made it clear that “they don’t know really what happened” with roughly $700 million in expenditures made during the early years of the project.

The project’s cost overruns and other challenges can be traced to the Hannemann administration, she said. “You do not issue contracts before an environmental impact statement is done, and when you do that, you’ve got these problems.”

Hannemann was mayor when the language for HART and its board was drafted and the agency was not set up to give board members authority to deal with its administrative functions, Hanabusa said.

Pine said that when she was in the Legislature, she initially voted against giving the city the use of state excise taxes for rail because the project looked underfinanced.

She chastised Hannemann for quitting two years into his second term as mayor in 2010 to run for governor “when we needed a strong leader to finish what you started.”

When she got on the Council in 2012, “we inherited a very big mess,” Pine said.

As mayor, she said, she would advocate that the federal government take over the project. “The temptation for corruption and cheating and mismanagement is too high,” she said.

Those found guilty of wasting taxpayers money “should go to jail,” Pine said.

That drew a sharp rebuke from businesswoman and community advocate Choon James, who said Pine “voted ‘yes’ for every project … you might go to jail yourself if the FBI does the work right.”

James said she wants the project stopped at Middle Street.

Former state Rep. William “Bud” Stonebraker pointed out that he voted against the rail tax when he was in the House. Construction should stop at the Middle Street transit station given the statewide economic woes, he said.

“We should shore up our finances at Middle Street and redirect and use our existing mass transit to get the thing working without expanding any further so that it can be used,” Stonebraker said.

Businessman Rick Blangiardi said he wants to see what bids coming in next month for a public-private partnership to help bring the project to completion have to show before making a decision on whether or how the project should proceed.

“This is about making the hard call on where we are in reality,” Blangiardi said. “We’ll see how it plays itself out. … It may very well be that we come to a temporary stoppage in a place nobody wanted, for four or five years.”

Former state Sen. John Carroll said anyone who’s been in elected office since rail began should not be considered for mayor. “We need to have a … forensic audit and we need to stop all construction until we know where we are, how much we owe, how much it’s going to take to go on and what are the options if we stop the rail even at the stadium or some other place.”

Businessman and former attorney Keith Amemiya, who sat quietly through the verbal back and forth, said “this exchange is … emblematic of what’s wrong in politics today. You’ve got people talking all over each other, you’ve got people saying others should go to jail, interrupting each other — that’s not my style of leadership.”

As for the project itself, “rail was a mess before construction started, rail was a mess during construction, but we need to sharpen our pencils and do what we can to complete the project at Ala Moana,” Amemiya said. “There’s too much at stake …. people are not going to ride the rail as much if it stops at Middle Street.”

The city can’t risk losing roughly $800 million provided for the project by the Federal Transit Administration, he said.

Thursday’s forum will be rebroadcast on KHET at 2 p.m. today. It also can be viewed on the show’s website at pbshawaii.org/insights/.

Unite Here Local 5, the hotel and restaurant workers union, hosted a separate 90-minute mayoral forum with six candidates that focused largely on union and visitor industry issues, including reopening the Waikiki visitor’s district. It can be viewed at the union’s Facebook page at facebook.com/uniteherehawaii/.