The US Court of Appeals for the Tenth ruled Wednesday that Kansas’s voter registration rules, which required documentation of citizenship, were unconstitutional and violated federal law.

The lawsuit had arisen as a challenge to former Kansas Secretary of State Kris Kobach’s well-publicized push to tighten control over voter rolls. But the state’s arguments about the necessity of doing so, the Tenth Circuit said, were insufficient to justify the burden the restrictions imposed on the constitutional right to vote.

The appeal concerned two consolidated cases over Kansas’s voter registration rules. One challenge contended that the requirement that people show citizenship documents violated the federal National Voter Registration Act (NVRA); the other contended that the rules were unconstitutional in violation of the equal protection clause of the Fourteenth Amendment. In 2016 the Tenth Circuit had held that the rules appeared in violation of the NVRA enough to justify a preliminary injunction. At a full trial with a further airing of the facts, a federal district court heard both claims and decided that under either theory, Kansas’s strict rules could not stand. “The magnitude of potentially disenfranchised voters impacted by the DPOC law and its enforcement scheme cannot be justified by the scant evidence of noncitizen voter fraud before and after the law was passed, by the need to ensure the voter rolls are accurate, or by the State’s interest in promoting public confidence in elections,” the lower court wrote. Wednesday’s decision by the Tenth Circuit Affirms that reasoning.

At the center of the issue was what the court called “scant” evidence that non-citizens were voting or attempting to vote in Kansas. That was the key belief underlying the state’s push to require voters to present documents like passports and birth certificates upon registration. But the new rules created complications that often burdened people’s constitutional right to vote when they struggled to obtain the required documents or bureaucratic application of the rules made registering a more onerous process. The trial court found that over 30 thousand Kansans had their voter registration suspended or applications canceled due to the rules. At the same time, “at most, 67 noncitizens registered or attempted to register in Kansas over the last 19 years.” This, the justification the state was using to burden the exercise of the right to vote for thousands of citizens, represented 0.002 percent of all registered voters at the time the rule went into effect, the court noted. Much of the purported non-citizen voting could even be explained by administrative error, the court reasoned: “For example, Kansas’s voter-registration database included 100 individuals with purported birth dates in the 19th century and 400 individuals with purported birth dates after their date of voter registration”—obvious clerical errors in numbers far greater than that shown for non-citizen registration.

“Thus, we are left with with this incredibly slight evidence that Kansas’s interest in counting only the votes of eligible voters is under threat,” the court wrote. Without a sufficient justification, the court then found the document requirements both unconstitutional and a violation of the requirements of the NVRA.