SIOUX FALLS, S.D. (AP) — The American Civil Liberties Union has filed a federal lawsuit challenging a South Dakota law that moved the deadline for new political parties seeking a spot on the 2016 ballot.

The ACLU filed the lawsuit on behalf of the Libertarian Party on Monday. The law challenged by the lawsuit is part a new bundle of changes that opponents say would discourage candidates from running for office.

The law being questioned shifted the deadline for new parties to submit declarations to participate in primary elections backward by four weeks. The plaintiffs are asking the deadline be set for no earlier than March 29 for a party that wants to participate in a primary election.

The lawsuit names Secretary of State Shantel Krebs as a defendant. She wasn't immediately available to comment.

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