Four campaign supporters of independent candidate for governor Eliot Cutler filed a lawsuit Monday against Maine’s ethics commission for not being allowed to contribute as much to Cutler as they could to a party candidate.

Amy Woodhouse and Richard Tobey Scott, both of Freeport, William Hastings of Falmouth and J. Thomas Franklin of Portland are named as plaintiffs in the lawsuit filed in U.S. District Court in Portland.

All four, according to the complaint, are concerned about “Maine’s two-tiered statutory scheme” that limits donations to non-party candidates such as Cutler.

Maine law allows party candidates to accept $1,500 contributions from individuals for both the June primary and the general election, even if those candidates don’t face primary challengers. Neither Republican Gov. Paul LePage nor Democratic U.S. Rep. Mike Michaud had a primary challenger, but each candidate is still allowed to accept as much as $3,000 from an individual.

As an independent, Cutler can collect no more than $1,500 per donor.

The lawsuit says that law should be struck down as unconstitutional.

“In Maine, all citizens do not enjoy this most basic right equally because under state election law as construed by the Commission, citizens who support candidates in the Republican or Democratic parties are permitted to contribute twice as much to the campaigns of their chosen candidates as citizens who support independent candidates,” the complaint says. “In other words, in the State of Maine, those who support Republican and Democratic candidates have a louder voice, and thus the ability to have a greater effect on elections, than those who support independent candidates. ”

Melissa Hewey, a Portland attorney who is representing the four plaintiffs, said Monday that she also is seeking a preliminary injunction that would allow contributors to give the maximum $3.000 to Cutler immediately. She has asked that the state respond within 10 days, instead of the 21 days normally allowed, because a prompt decision could impact the campaign.

Maine Attorney General Janet Mills, whose office will represent the Ethics Commission, said late Monday that “the case will be assigned to our professional nonpartisan staff attorneys to draft an appropriate response.”

Also named as defendants were Walter McKee, chairman of the Ethics Commission, and Secretary of State Matthew Dunlap.

Dunlap said he’s not sure why he was named.

“My office has nothing to do with campaign finance,” he said.

This particular provision of campaign finance law has never been challenged in Maine, Hewey said, but she pointed to a recent precedent in another state.

In January, the 10th U.S. Circuit Court of Appeals struck down a Colorado law that allows Democratic and Republican candidates to collect $400 per donor but limits unenrolled candidates to $200.

“We are aware of this lawsuit and are pleased that the plaintiffs have taken on this issue,” Cutler said in a statement. “Maine people understand fairness and it has long been unfair that the political parties in Maine have created one set of rules for their candidates and another for Independents.”

Cutler’s campaign has talked often about the inequity of Maine’s law.

He has been able to raise a significant amount of money and has supplemented that with $500,000 from his own pocket. Cutler has said repeatedly that he is willing to donate the resources necessary to run a successful campaign. In an email to supporters last month, he said he would match all donations until July 15, a reaffirmation that he’s “all in.”

But Cutler has also spent the most, and by a good margin.

As of late May, he had spent more than $1.25 million since January 2013. That dwarfs LePage, who has spent about $261,000, and Michaud, who has spent $756,000, much of it on fundraising services.

Cutler’s campaign had just $40,000 in cash as of May 27, compared to $864,000 for Michaud and $758,000 for LePage.

Ben Grant, chairman of the Maine Democratic Party, issued a statement Monday night criticizing Cutler and the lawsuit.

“Eliot Cutler had ample time over the past four years to participate in reforming campaign finance laws by working with his local legislators, but he’s been completely absent from this debate in Augusta,” Grant said. “Instead of rolling up his sleeves and making the case to the Legislature, he’s now running to the Courthouse. The people of Maine want leaders to come together and solve problems, not governing by lawsuit.”

The Maine Republican Party also weighed in on the matter.

“It’s hard not to sympathize with the Cutler campaign’s built-in fundraising disadvantage, especially on a day that we find out Michaud will be benefiting from another $2 million in PAC money being pumped into the state by government employee labor unions and others,” David Sorensen, communications director for the party, said in a statement.

Lizzy Reinholt, spokeswoman for Michaud, said the campaign wanted to learn more about the lawsuit before commenting. Alex Willette, spokesman for LePage’s campaign, also said he wanted to review the complaint before commenting.