AUGUSTA — Supporters of independent gubernatorial candidate Eliot Cutler filed a lawsuit in U.S. District Court Monday, alleging that Maine’s current election laws unfairly prevent them from giving as much money to Cutler as backers of party candidates can donate to their preferred nominee.

If the court rules in their favor, it could create complications for future elections in the Pine Tree State, according to some national election and campaign finance experts.

In Maine, individual contributions to political candidates are capped at $1,500 per election. Primaries — the tool used by political parties to select nominees for office — are considered elections, so Democratic and Republican candidates may accept $1,500 from an individual twice — once for the primary and, if they win, once again for the general election.

Independent candidates such as Cutler don’t run in primary elections. They qualify for the general election ballot by collecting 4,000 certified signatures by Maine voters. They only run once. So, according to Maine law, they can only collect up to $1,500 from any particular contributor.

This year, Cutler faces two party candidates, Democrat Mike Michaud and Republican incumbent Gov. Paul LePage, who were unopposed in their primaries. However, Maine law still allows them to collect up to $3,000 from any one donor.

On its face, the system seems pretty obviously unfair, said Paul Ryan, senior counsel for the Campaign Legal Center, a Washington, D.C.,- based nonprofit that represents the public’s interest in media and campaign law.

But, Ryan said, other campaign contribution cap scenarios are equally troubling: If an independent in Maine were able to raise $3,000 for the general election, it would put that candidate at an unfair advantage over party candidates in competitive primaries, who would essentially have to wage two campaigns while the independent only needed to focus on one.

Another option, Ryan said, would be to have different caps based on whether a party primary was contested or not. If the primary were competitive, the party candidate would be allowed to max-out donors twice. If not, contributors could hit the $1,500 cap only once.

However, that option could not account for a strong write-in candidate, which would essentially force a party candidate to wage a real primary campaign despite being the only man or woman officially on the ballot.

“I understand the concerns being raised on the part of the independent candidate, but there are some pretty good public policy reasons the law works the way it works,” Ryan said.

Twenty-five states have campaign contribution limits set up the same way as Maine’s, where donors can max out their contributions once per election, according to October 2013 data from the National Council of State Legislatures. Another 13 states have per-election cycle or per-year contribution limits, and 12 states have no contribution limits at all.

The purpose of per-election limits is to prevent candidates from amassing huge sums of money from individuals up-front, said Edwin Bender, executive director of the National Institute on Money in State Politics in Helena, Montana.

But in a state with a history of strong independent candidates, who don’t wage primary campaigns, the reason for having the per-election cap is “essentially sidestepped.”

Still, Bender said it’s important to realize that few Mainers reach the contribution cap, and even fewer max out their donations twice. Only about 330 individuals and companies have maxed out their contributions to Cutler, who has received more than 2,200 contributions so far this election cycle.

About 450 contributors maxed out for Michaud in the primary, and another roughly 170 have maxed out, so far, for the general election. The Democrat has received more than 6,400 contributions so far.

For LePage, about 240 donors have maxed out at least once, and roughly 115, so far, have maxed out twice — out of more than 2,300 contributions so far.

“From a legal standpoint, it’s a question that needs to be addressed,” Bender said. “But we’re talking about a very small number of donors. That’s the reality of campaign finance in this country, but that doesn’t address the legal question of fairness.”

A per-election contribution limit similar to Maine’s was struck down in Colorado by the 10th Circuit Court of Appeals in January. The four Cutler supporters who filed the lawsuit Monday are seeking a similar result, but the ruling in the 10th Circuit is not binding in Maine, so it’s anyone’s guess how the court will rule.

For B.J. McCollister, program director for Maine Citizens for Clean Elections, the court’s ruling doesn’t much matter. The average Mainer can’t afford to max out their financial support for a candidate once, let alone twice, he said.

“Whether it’s $1,500 or $3,000, both are far out of the reach of the average Mainers’ contribution limit,” he said. “This shows once again that this gubernatorial election is about large donors, and not regular Mainers.”