U.S. District Judge Julie Robinson on Monday ruled a Kansas law that requires new voters to prove citizenship is unconstitutional and ordered Kansas Secretary of State Kris Kobach to return to school as punishment for repeated violations of court rules.

Her 118-page ruling sides with the American Civil Liberties Union in a two-year legal battle over the law's burden and effect on elections. She provided a damning assessment of Kobach's witnesses, calling their evidence flawed, invalid, biased, irrelevant, unreliable and untrustworthy.

Robinson also takes aim at Kobach for "repeated and flagrant violations" of court procedures during the March trial. His repeated last-minute efforts to introduce new evidence showed a pattern of "flaunting disclosure and discovery rules that are designed to prevent prejudice and surprise at trial," she said.

As a sanction, Kobach must take six hours of continuing law education in addition to any hours required for his law license.

Danedri Herbert, a spokeswoman for Kobach, said the ruling is unlikely to survive an appeal.

"Robinson is the first judge in the country to come to the extreme conclusion that requiring a voter to prove his citizenship is unconstitutional," Herbert said. "Her conclusion is incorrect, and it is inconsistent with precedents of the U.S. Supreme Court."

Kobach has insisted the known instances of voter fraud represent the "tip of the iceberg," but Robinson said the "more obvious conclusion" is there is "only an icicle." Micah Kubic, executive director of the ACLU of Kansas, said the ruling establishes that voting restrictions are "illegal, unconstitutional and just plain wrong.

"His 'papers please' requirement runs counter to the values that we share as Kansans and Americans," Kubic said. "Our democracy is strongest when more citizens vote, not when fewer do. These requirements have had one purpose only — to decrease citizen participation in Kansas elections in ways that weaken our democracy."

The Legislature in 2011 passed the Secure and Fair Elections Act with overwhelming, bipartisan support. It requires anybody who registers to vote to provide a proof of citizenship document, such as a birth certificate. The ACLU filed a lawsuit challenging the law in 2016 and secured a preliminary injunction based on the likelihood the law was unconstitutional.

A federal appeals court upheld the injunction and demanded Kobach prove his claims of widespread voter fraud at trial.

In her ruling, Robinson excluded one of Kobach's experts, found another to be unqualified and undermined the value of a professor Kobach relied on for what he called the best possible estimate of voter fraud.

Jesse Richman, who teaches political science at Old Dominion University, based his conclusions on surveys with small sample sizes and didn't weight the responses for demographics. In one example, he pointed to four out of 14 survey responses to conclude that 28.5 percent of the estimated 114,000 noncitizens in Kansas registered to vote. In doing so, he failed to verify whether the people who responded were actually noncitizens.

In another example, he surveyed Kansans with temporary driver's licenses. Six of the 36 who responded said they attempted to register to vote. When an ACLU witness checked the state's database, however, none of them had actually tried to register.

Only 127 noncitizens are believed to have attempted to register to vote. Of those, only 39 succeeded and only 11 voted. Some of those were the result of poor training at DMVs.

"This trial was his opportunity to produce credible evidence of that iceberg, but he failed to do so," Robinson said. "The court will not rely on extrapolated numbers from tiny sample sizes and otherwise flawed data. Dr. Richman’s estimates were not only individually flawed and wildly varied, but his refusal to opine as to the best method of estimating the iceberg renders them all suspect."

Pointing to Kobach's "well-documented history of avoiding this court's orders," she ordered him to update all election materials, including information on his website, and make clear to all election officials in Kansas that they can't enforce proof of citizenship requirements. Kobach and the ACLU must confer 30 days before the primary election to verify compliance.

ACLU attorney Dale Ho called Robinson's decision "a stinging rebuke" of Kobach and the "centerpiece of his voter suppression efforts."

"That law was based on a xenophobic lie that noncitizens are engaged in rampant election fraud," Ho said. "The court found that there is 'no credible evidence' for that falsehood."