The American Civil Liberties Union is challenging a two-tiered election system that require Kansas election officials to throw out thousands of votes cast in state and local races by people who registered at motor vehicle offices or used a federal form without providing documentary proof of their U.S. citizenship.

The class-action lawsuit filed Tuesday in Shawnee County District Court comes a week after a state board approved the temporary measure. The board’s decision was made a day before advance voting began for the Aug. 2 primary.

The rule was sought by Secretary of State Kris Kobach and will be in effect through the Nov. 8 general election.

A federal judge in May ordered the state to allow people who registered at motor vehicle offices to vote in federal elections.