AUGUSTA — A U.S. District Court judge has ruled the state must allow supporters of independent gubernatorial candidate Eliot Cutler to contribute as much to his campaign as supporters of his partisan opponents.

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.

Supporters of partisan candidates are allowed to give the full $3,000 even after it’s clear that there will be no primary opponent for their candidate to face. It’s only after the primary election is held that new contributors are limited to giving $1,500.

Cutler is running against incumbent Republican Gov. Paul LePage and Democratic U.S. Rep. Mike Michaud. Neither faced a primary opponent this year.

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 run only once. So, the state argued they could collect only up to $1,500 from any particular contributor.

In early July, Cutler supporters Amy Woodhouse of Freeport, Richard Tobey Scott of Freeport, William Hastings of Falmouth and J. Thomas Franklin of Portland, filed the lawsuit against the Maine Ethics Commission, arguing the contribution limits violated their Constitutional rights.

Judge D. Brock Hornby wrote in his ruling Friday that because neither LePage or Michaud had to wage a primary campaign this year, it was wrong for their supporters to be allowed to give twice as much as Cutler’s.

“Although the State’s lawyers speculate that even an uncontested primary might require some action by the party candidates, there is no evidence of that at all,” he wrote.

Hornby also mentioned that independent candidates may face a disadvantage even if their partisan opponents face primary challenges, saying independents may have to “find an equivalent way to achieve name recognition and public attention so as not to be late off the mark for the general election at the close of primary season.”

The ruling issued by Hornby on Friday was a not a decision on the constitutional questions raised by the plaintiffs, but a preliminary injunction against the state, ruling that the state must immediately allow Cutler’s supporters to donate up to $3,000.

“The plaintiffs’ right to exercise their First Amendment rights equally with other contributors should not be delayed,” Hornby wrote. “And their exercise of those rights does not seriously affect the First Amendment rights of other contributors to exercise their similar rights. So I see no reason to delay the increase in the contribution limits.”

It is not immediately clear whether the state will appeal Hornby’s injunction.

Cutler said in a written statement Friday that he was “gratified” the court favored his supporters’ position.

“This ruling eliminates a longstanding fundraising advantage party candidates had over non-party candidates,” he said. “I am grateful to the citizens who stepped forward to challenge the law and am pleased that Judge Hornby saw the merits of their case.”