The Pacific Resource Partnership, which supports the city’s rail project, has spent more than $1 million since January on political advocacy with most of the money used to attempt to influence the mayoral election.

The group’s political action committee, financed by the Hawaii Carpenters Union and contractors, has directed most of its advertising at former Gov. Ben Cayetano, who has vowed to stop the $5.26 billion project if elected mayor.

But PRP’s independent spending has not changed public opinion on rail or on Cayetano, who faces Mayor Peter Carlisle and former managing director Kirk Caldwell in the primary. The latest Hawaii Poll showed that about half of Oahu voters do not want work on rail to continue — about the same as the last Hawaii Poll in February — and had Cayetano in the lead in the mayor’s race with 44 percent of the vote — the same as in February.

"We are giving voice to the many people in our industry and throughout Oahu that do not want to return to the corrupt days of ‘pay-to-play’ that flourished under Ben Cayetano," John White, PRP’s executive director, said in a statement. "Cayetano, through his cronies and intermediaries, have tried to bully and intimidate us into silence. Voters deserve to know the full truth of Cayetano’s record as governor."

Former Campaign Spending Commission Executive Director Bob Watada, who led the crackdown on the "pay-to-play" culture of the 1990s, has called the ad campaign "bogus"; the commission has said Cayetano did nothing illegal.

Cayetano said PRP’s campaign has backfired.

"It’s the impression I get from the street, anyway," he said. "I wish they spent another million dollars attacking me."

All of the money for PRP’s political action committee came from the Hawaii Carpenters Market Recovery Program Fund, which is made up of contributions from 6,500 union carpenters and the contractors who are signatory to the union. Under state campaign finance law, the group’s political action committee is not required to disclose the individual contractors who contributed to the market recovery program. PRP has declined to voluntarily identify the contractors.

Others in the labor movement, speaking privately, said PRP’s advertising against Cayetano has been shrill and ineffective.

With Cayetano likely to advance to a November runoff — if not win outright in the primary — many in labor who support Caldwell and want the rail project to proceed have chosen to wait for the general election rather than follow PRP, which, as one labor leader put it, would be throwing "good money after bad."

Public sector labor unions that clashed with Cayetano about binding arbitration and civil service reform when he was governor will likely join the construction unions that want rail in publicly criticizing Cayetano if there is a general election.

The latest campaign finance reports for the mayor’s race were also released on Wednesday.

Caldwell raised the most during the first three weeks in July — $273,650, including a $50,000 personal loan to his campaign. He has raised $875,500 overall and had more than $133,300 in cash on hand.

Carlisle raised $101,200 in July and has brought in more than $739,300 overall. The mayor had $118,000 in cash on hand.

Cayetano raised more than $57,500 in July and has collected more than $950,500 overall. The former governor had more than $315,550 in cash on hand.