How big a deal is $5? We are about to find out.

Fake $5 contributions to John Richardson’s gubernatorial campaign resulted in him dropping out of the race Monday, just six weeks before what would have been a five-way Democratic primary.

Although Richardson and his campaign manager are not accused of any wrongdoing, volunteers on his campaign are alleged to have claimed contributions from people who say they didn’t give.

After problems appeared in a routine follow-up call to randomly selected donors who reportedly helped Richardson reach the Clean Elections fund threshold of 3,250 $5 checks, investigators made more calls. They contacted 109 people on Richardson’s donor list and found 39 who said they signed a form, but were either never asked or had refused to donate.

As a result, the ethics commission staff rejected Richardson’s application for Clean Elections funding and Richardson chose not to appeal, noting the short time left before the primary and the taint that would follow his campaign even if he was successful.

The Maine Commission on Governmental Ethics will meet Thursday, and although the case is essentially closed as far as they are concerned, they should officially refer the matter over to the Attorney General’s Office to investigate whether there was any criminal wrongdoing in this matter.

The percentage of donations that were faked suggests that this is more than just sloppy paperwork. If even low-level volunteers were intending to defraud the Clean Election fund, which would have given Richardson $400,000 in public money to spend on his campaign, that amounts to a major scandal.

The losers include the thousands of Mainers who contribute to the fund because they wanted to minimize the influence of money on campaigns, Richardson’s legitimate contributors and the candidate himself, who may have collected enough real $5 checks to qualify without the “help” he received. There ought to be a thorough investigation into every single contribution record and a determination made of how these false ones found their way into the report.

If anyone’s actions are determined to be criminal, then that would be a very big deal, indeed.