Perhaps it was only a matter of time before the advent of “super PACs” — a variant of the political action committee (PAC) — developed a higher profile in Hawaii politics.

Six years ago, a super PAC formed to raise money for advertising in opposition to former Gov. Ben Cayetano in his bid to defeat Kirk Caldwell in the mayoral race. The committee was backed by the pro-rail Pacific Resource Partnership consortium, and Cayetano was an avowed opponent of the city project.

That group made a big splash, and now the super PAC factor in the current election cycle has intensified. It’s something that bears watching by local residents, who ultimately still control whether or how campaign messaging will influence their vote.

This time, the attention-getter is “Be Change Now,” a super PAC pumping hundreds of thousands of dollars into the most competitive races, financed by the Hawaii Regional Council of Carpenters. It is particularly active in the Colleen Hanabusa and Josh Green campaigns for governor and lieutenant governor, respectively.

Super PACs were enabled in 2010 by two key court cases, Citizens United v. Federal Election Commission and Speechnow.org v. FEC. Taken together, the cases cleared the way for super PACs to function as “independent expenditure” groups.

They can spend an unlimited amount of money for communication in support of, or opposition to, candidates, as long as they do so without coordinating with any candidates. And unlike a regular PAC, they cannot donate money directly to candidates.

Clearly, though, they can have an outsized effect on voter impressions of the candidate because of the volume of advertising.

There are federal requirements for super PACs to disclose the identities of donors, but many have taken advantage of the workarounds. Corie Tanida, executive director of the good-government nonprofit Common Cause Hawaii, said that even if donors are listed, it’s impossible to prove whether they are simply the fronts for unnamed contributors — sources of the so-called “dark money” noted in national campaigns.

It’s unknown how much of an effect that has in local PAC activity, but in 2013 the Legislature passed House Bill 1147, enacted as Act 112, to enhance disclosure of major contributors. Under the law, advertisements must contain an additional notice starting with the words, “The three top contributors for this advertisement are,” followed by the names.

There was an attempt to blunt that requirement in this past session. Lawmakers passed Senate Bill 2992, which would have excluded signs and banners from being considered as advertising. Gov. David Ige rightly vetoed the bill, expressing concern in his veto notice that “exempting signs and banners from certain election law disclaimer requirements will reduce transparency in campaign finance.”

Of course, defenders of super PACs will point out that these groups enjoy the free-speech protections of the First Amendment. Others on the national stage make the observation that more spending does not necessarily deliver electoral success; in fact, some argue that, dollar for dollar, super PACs aren’t especially effective and have not swamped elections as much as it was feared.

On the local level, their impact has not yet been fully documented. But voters should not wait for that to happen. When hearing noise from the campaign trail, Hawaii residents should make note of its source.

And they need to seek out information from the politicians themselves, on how they will address the state’s shortcomings in housing, land use, public education, the economy. If candidates can’t convince the voters themselves, they really haven’t earned the vote.