KANSAS CITY, Mo. � Missouri�s voter ID law is facing a legal challenge from a national progressive organization alleging it creates undue burdens for voters who lack the required photo identification.

The Democratic-aligned Priorities USA filed the lawsuit on behalf of Mildred Gutierrez, 70, of Jackson County, The Kansas City Star reported.

The law, approved by Missouri voters in 2016, allows a person without a photo ID to cast a ballot if he or she signs a sworn statement attesting he or she doesn�t have required documents.

But the lawsuit alleges these procedural hurdles are �fraught with uncertainty and unwarranted threats of criminal penalties.� The required statements are signed under penalty of perjury and contain �confusing and threatening provisions that discourage qualified voters from attempting to exercise their right to vote without Photo ID,� the lawsuit claims.

Gutierrez has been a registered voter for more than 40 years and has even served as an election judge in Jackson County, according to the complaint.

Gutierrez�s driver�s license expired in 2016 and she wasn�t eligible for renewal because of her failing vision, the lawsuit states. Gutierrez signed the sworn statement in order to vote in a Missouri state Senate special election in November. Gutierrez was then informed she wouldn�t be allowed to vote in future elections without a non-driver�s license ID from the state, according to the suit.

The suit comes roughly five months before Missouri residents will vote in a race that could determine control of the U.S. Senate.

�We have received the complaint, and we intend to fully and fairly defend Missouri law,� said Mary Compton, a spokeswoman for Attorney General Josh Hawley. Hawley is a Republican candidate in the race.

Priorities USA Action, the group�s political action committee, has spent more than $430,000 on the 2018 U.S. Senate race. Data analyzed by ProPublica found most of that money was spent on attack ads against Hawley.

�We have been on the forefront of filing suits like this across the country because we believe there shouldn�t be impediments to the ballot box for anyone at any time � whether it�s an election year or not,� said Symone Sanders, Priorities USA�s spokeswoman.