MINNEAPOLIS (CN) – Minnesota Libertarians brought a federal complaint Wednesday over a state law that bans voters who sign their party petitions from voting in primary elections.

The statute at issue requires anyone who signs a ballot petition for a minor political party to take an oath not to vote in the state’s upcoming primary election. Violations of the law are punishable by up to five years in prison and $10,000 in fines.

No similar sanction is imposed on ballot petitions for Democratic or Republican ballot issues.

Joined by four individual voters, the Libertarian Party filed suit in Minneapolis on Wednesday, alleging violations of the First and 14th Amendments. They say the law deters potential signers and violates a person’s right to vote.

“Thus, if a person signs the petition and later changes his or her mind, the person cannot exercise their constitutionally protected right to associate and vote,” says the complaint, which was brought by the law firm Mohrman, Kaardal & Erickson.

“Further,” it continues, “comparing supporters of minor parties to supporters of the major parties, the petition signatories are not treated equally as other primary voters. Primary voters should not be excluded from the primary election process just because they saw fit to provide all voters a greater choice of candidates than the major parties provide. Notably, the statute deters potential petition signatories because of governmental interference with subsequent primary election opportunities and the threat of prosecution for signing the petition in the first instance.”

In addition to creating a chilling effect on voters signing petitions, according to the complaint, the law could ultimately reduce the number of candidate choices for voters. The law creates a 14-day window for minor party candidates in late May, which includes Memorial Day weekend, to collect the required signatures to get on the ballot. For House races, 500 signatures are needed. For statewide races, 2,000 signatures are needed.

Democratic and Republican candidates don’t have such time constraints.

The individual plaintiffs say they have been active within the state’s Libertarian Party, including helping with a petition drive to get Gary Johnson and William Weld on the state’s 2016 ballot as president and vice-president candidates, respectively.

“The 2016 petition drive created more confusion about the oath and its relevance, since Minnesota was not a presidential primary state at that point and the caucus process for that position had already occurred earlier in the year,” the complaint states.

“Specifically, potential signers were confused about the necessity of swearing the mandatory oath and promising not to vote in a primary election contest with the potential for criminal penalties when there was no presidential primary in 2016.”

This resulted in many voters refusing to sign the petition, according to the complaint.

Similar issues have allegedly come up in trying to get candidates on the ballot in state races.

Chuck Laszewski, a spokesman for the Hennepin County Attorney’s Office, said his office had not been served with the lawsuit and therefore had no comment. Hennepin County Attorney Mike Freeman is one of three defendants to the suit. Ramsey County Attorney John Choi and Anoka County Attorney Tony Palumbo did not return requests for comment.