Opponents of same-day voter registration have made protecting the “integrity” of elections a centerpiece of their campaign. So it is odd that they are having a hard time following election laws and protocols.

Earlier this week, Secure Maine Votes, the political action committee advocating a “no” vote on Nov. 8’s Question 1, was fined by the state Ethics Commission for failing to disclose expenditures in a timely manner.

Question 1 seeks to overturn a law passed by the Legislature earlier this year that would end same-day voter registration. Backers of the law say the change is needed to prevent voter fraud, despite evidence that voter fraud is extremely rare in Maine.

Supporters of Question 1 say same-day voter registration increases voter participation — which is backed up by several studies — and is necessary for cases where there are mistakes in voter rolls that may preclude qualified voters from casting a ballot.

In recent days, Secure Maine Votes spent about $300,000, even though its most recent campaign finance report, on Oct. 25, showed only $36,000 in donations.

During the last 13 days leading up to an election, Maine law requires political action committees to file reports on any expenditures of $500 or more within 24 hours of the expenditure. PACs are not required to report contributions received in that same period.

According to Cindy Sullivan with the ethics commission, Secure Maine Votes spent $162,000 on television advertising on Oct. 28. The expenditure report, however, was not filed until Monday, Oct. 31, beyond the 24-hour requirement.

As a result, the group was fined $3,251 by the ethics commission.

While the law requires reporting of expenditures, it does not require that contributions be revealed. So, while we know that billionaire hedge fund manager Donald Sussman, who is married to 1st District Rep. Chellie Pingree, bankrolled the Yes on 1 campaign, we don’t know who funded the No on 1 side.

This lack of disclosure doesn’t increase election integrity. Quite the opposite, in fact.

“It’s not unusual for PACs to get a large infusion of cash in the last few weeks to get their message out to voters,” Jonathan Wayne, director of the Maine Ethics Commission said Tuesday. “But I think there is a feeling that people should know where that money comes from.”

Further, while not against the law, Question 1 opponents have also printed political handouts and signs with no disclosure of what group or person paid for them. Typically, campaign literature includes disclosure — a website, at least — of what group distributed the material.

A spokeswoman for the No on 1 campaign, Jen Webber, dismissed concerns about her group’s disclosure problems as “fascination with the idiosyncrasies of campaign finance reports” and as “the kind of politics as usual that the people of Maine are sick of.”

Disclosing who pays to defeat (or support) a ballot measure is not an idiosyncrasy. It is, to quote from a No on 1 handout, a key element of protecting “the integrity of Maine’s election process.”

If all of this weren’t bad enough, Secure Maine Votes has begun airing a short TV commercial that confuses the whole issue by suggesting that Question 1 is about repealing Maine’s “ethics law.”

The brief spot asks: “Who should decide Maine’s elections, Mainers or outsiders from other states? Today, outside interests are trying to get rid of Maine’s ethics law. Keep Maine’s elections fair. Keep Maine’s elections decided by Mainers. Vote no on Question 1.” It does not mention voter registration at all.

Asked what ethics law the commercial was referring to, Ms. Webber said she didn’t know because the ad was produced by an “outside agency.”

Misleading ads and skirting disclosure laws are the antithesis of integrity. Maine voters deserve better.