In an attempt to get its candidates back on the Montana ballot this fall, the Montana Green Party has sued the state in federal court, seeking to void part of Montana’s requirements for political parties to qualify for the ballot.

The lawsuit, filed late Monday, says Montana’s ballot-qualification requirements are among the most restrictive in the nation — and an unconstitutional barrier to smaller, unestablished political parties.

The suit asks a federal judge to strike down the requirements and order Montana Secretary of State Corey Stapleton to place five Green Party candidates back on the November ballot.

Green Party Coordinator Danielle Breck said the suit is in response to the Montana Democratic Party’s lawsuit and subsequent state court order in July that removed Green Party candidates from the ballot.

“We cannot and will not sit idly by and allow the Democratic Party to silence the voices of the thousands of Montanans who believe in our Green movement,” she said in a statement. “We are moving this discussion to federal court where it belongs.”

Breck said the deadline for making any changes to the November ballot is Aug. 23.

In the lawsuit brought by the Democratic Party earlier this year, state District Judge James Reynolds of Helena invalidated 82 signatures submitted on petitions by the Green Party to qualify for the ballot.

Once those voter signatures were invalidated, the Green Party did not have enough signatures to meet a minimum threshold in at least 34 state House districts – a “distribution” requirement in state law for parties to qualify.

Five Green Party candidates were removed from the ballot after Reynolds’ ruling: U.S. Senate candidate Steve Kelly, U.S. House candidate Doug Campbell and three legislative candidates.

The state has appealed Reynolds’ ruling to the Montana Supreme Court, which has yet to rule.

Monday’s lawsuit says the distribution requirement is unconstitutional because it “works in an unequal and discriminatory manner.”

“If not for the unconstitutional state House district distribution requirement, the Montana Green Party would have had more than enough petition signatures for political party recognition in Montana in 2018,” the suit said.

To qualify its candidates for the 2018 ballot, the Green Party had until the first week of March to submit petitions with the signatures of at least 5,000 registered Montana voters. Under the distribution requirement, the party also had to submit a minimum amount of signatures in at least 34 of the state’s 100 House districts.

That minimum is 5 percent of the vote total that the winning gubernatorial candidate had in each district in 2016, or 150 signatures in each district – whichever is lower.

The Green Party submitted petitions with 7,386 valid signatures statewide and initially met the distribution requirement in 38 House districts. Stapleton’s office certified the party for the ballot on March 12, the last day that candidates could file for office in 2018, and the Green Party candidates filed that day.

The state Democratic Party’s lawsuit, filed several weeks later, alleged that scores of Green Party signatures submitted were not valid. Reynolds agreed that 82 signatures were invalid, and removing those signatures meant the Green Party had met the minimum in only 30 House district – less than the required 34, and thus disqualifying the party for the ballot.