Susan Collins, left, and Sara Gideon Credit: Patrick Semansky and Robert F. Bukaty | AP

AUGUSTA, Maine — Campaign finance complaints have piled up in Maine’s high-profile U.S. Senate race, even as some of the charges against the Republican incumbent, her top Democratic challenger and allies may not be ruled on before the election or lead to major fines.

The latest charge was made last week against Sen. Susan Collins over spending related to her exploring a run for governor in 2017. It followed two complaints against House Speaker Sara Gideon, one of four Democrats running for the nomination to face Collins, and others against a group backing the Republican incumbent.

Although only one of the complaints has been adjudicated so far — amounting to a state penalty of $500 against Gideon — campaigns and outside groups are flogging the allegations ahead of what will likely be the most expensive political race in Maine’s history.

They may not generate heavy penalties, but the complaints can give the sides messaging sugar highs and retaliatory strikes. That is why many have been lodged with likely more to come.

The complaints against Collins and Gideon have been promoted by partisan groups, including a new and unusual complaint against the incumbent. The newest charge, filed by a South Portland resident last week, argues that polling paid for by Collins’ federal campaign in 2017 was an in-kind contribution that exceeded state limits.

When Collins was publicly considering a run for governor, her Senate campaign committee paid a polling firm $61,000 for two surveys, according to filings with the Federal Election Commission, which, according to an internal memo obtained by a Bangor Daily News columnist, asked about Collins’ approval rating and how she would fare in a gubernatorial election.

The complaint alleges that the polling counted as an illegal campaign contribution, citing a provision in Maine law saying any “funds, goods or services” received for “the purpose of deciding whether to become a candidate” were not allowed to exceed $1,600 in 2017.

What makes the ethics complaint against Collins unusual is that the senator never set up a state-level campaign because she opted not to run for governor, setting up a legal question about whether the Maine Ethics Commission has jurisdiction over a federal committee.

The state regulator will decide on the complaint in the coming months. It also has to rule on a complaint the Maine Republican Party filed against a political committee once run by Gideon, alleging that it had failed to report spending on Facebook ads in 2018.

It’s the second complaint against Gideon’s now-terminated committee. A Republican lawmaker filed a complaint against it last fall after an article in the conservative-leaning Washington Free Beacon alleged that the House Speaker had improperly reimbursed herself for campaign contributions in 2015 and 2016. The Maine Ethics Commission issued a fine of $500 while saying that it didn’t believe Gideon intended to break the law.

The liberal advocacy group End Citizens United, which promoted the complaint against Collins and has endorsed Gideon, said in a Tuesday statement that the senator should “come clean” about the 2017 polling. A Collins spokesperson shot back by calling the allegations a “blatant attempt to try and distract attention” from the complaints against Gideon.

A nonprofit has also filed a complaint regarding a group supporting Collins — but a federal regulator is unlikely to rule on it and other complaints in the race. 1820 PAC, a super PAC formed to help Collins’ re-election, faces its own federal campaign finance complaint stemming from a $150,000 contribution it received from a Hawaii-based company. The Campaign Legal Center, a nonprofit known for challenging Democrats and Republicans on campaign finance laws, filed the complaint in early February.

It alleges that the company was formed in order to conceal the source of the $150,000 contribution, violating a federal law that prohibits making political contributions in the name of another person. Reporting from Hawaii Civil Beat suggested that the contribution might be linked to the CEO of Navatek, a major defense contractor.

It is unlikely that the allegations will be evaluated before November, since the Federal Election Commission, which handles federal ethics complaints, usually takes several years to evaluate them and does not have enough commissioners to hold a formal vote on enforcement action.

The same goes for federal complaints that Maine Republicans made in relation to Gideon’s state-level committee and a complaint last year from the Maine Democratic Party against 1820 PAC alleging that an ad by the group used too much footage put online by Collins’ campaign.