A years-long dispute over the failure of a pro-rail political action committee to disclose campaign expenditures it made against former Gov. Ben Cayetano in his 2012 bid for mayor will be resolved with a state-imposed fine.

The state Campaign Spending Commission voted Wednesday to assess a $1,250 fine in the case brought by Cayetano.

Cayetano came out of retirement in 2012 to run for mayor, pledging to stop the city’s rail project if elected. The Pacific Resource Partnership Political Action Committee, representing a consortium of union carpenters and private contractors, spent more than $3.7 million in ads, opinion polls and other outreach against Cayetano, who ultimately lost the election to Kirk Caldwell.

Cayetano alleged in a 2014 complaint to the state Campaign Spending Commission that PRP and its former chairman and treasurer, John White, violated campaign laws when it failed to report $363,478 the PAC spent on consultants who helped with the campaign.

The commission voted in late 2014 to refer the case to the attorney general for criminal investigation and possible prosecution. Commissioners at the time reserved jurisdiction over the matter if the Attorney General’s Office declined to press charges.

More than two years later, at the commission’s July meeting, the Attorney General’s Office informed the panel that it declined to pursue criminal charges due to a “procedural defect.” The office also said there was insufficient evidence to prove a criminal violation in a separate complaint against PRP and White for failing to report $86,183 that PRP spent on mailers in support of City Councilwoman Carol Fuku­naga in 2012.

Campaign spending commissioners assessed the $1,250 fine in the Cayetano case, as well as a $1,000 fine in the Fukunaga case.

Attorney William McCorriston, who represents White, said his client is willing to pay the fines to resolve the cases.

“PRP and Mr. White would like to bring these matters to a close. They have been ongoing for 3-plus years and relate to an election that took place almost 5 years ago,” McCorriston said in an email to the commission, which he later provided to the Honolulu Star-Advertiser.

McCorriston said PRP and White — who left his post at PRP last year — contend the disputed $363,000 in campaign expenses “did not clearly fall within the statutory definition of ‘expenditure’” and that the failure to disclose the $86,000 payment in the Fukunaga case was inadvertent. Still, he said, “PRP is willing to pay the proposed fines … to close out these matters.”

PRP said in an emailed statement: “We are pleased that this matter has been resolved. … Governor Caye­tano’s desperate five-year effort to punish PRP for helping to sink his candidacy has come to an end, and it is time for everyone to move on.”

Cayetano could not be reached for comment Wednesday.

Commissioner Gregory Shoda said it was unfortunate the AG declined to pursue the cases. “There’s so much money moving around (and) the public doesn’t have input,” he said. “But we are left where we are because they declined prosecution.”