KANSAS CITY, Kan. In mid-October, on the last day he could register to vote ahead of the Nov. 4, 2014, midterm elections, Charles Stricker went to the DMV in Wichita. When he checked in, Stricker, who had just moved to Kansas, was told he didnt have all the documents he needed to get a drivers license. So he went home, put all the documents together and rushed back to the DMV. He wanted to make sure he got there in time because at the DMV he could do both: get his license and register to vote in time.

He showed the DMV clerk the folder of documents he brought, including his birth certificate from Missouri, and thought he had successfully registered to vote. The officials at the DMV told him his permanent license and voter information would come in the mail in a few weeks.

Stricker, who is 37 and works as a hotel manager, went to vote with his wife when the polls opened on Nov. 4. By that time he had gotten his permanent drivers license, but when he went to sign in at the polls, they told him his name wasnt on the list. He thought it was a mistake, maybe because he had registered at the last minute, and he asked to speak with the person in charge to try and figure out what the problem was. Eventually he was given a provisional ballot, but instead of getting a private booth to fill out his ballot like everyone else, he was sent to a white plastic table, where everyone could see how he was marking his votes. He could see who the person next to him was voting for, and he was pretty sure she could see who he was voting for. He said he felt humiliated.

Since 2013, Kansas has required anyone who registers to vote to prove they are a U.S. citizen. Even though Stricker had brought his birth certificate to the DMV that day, election officials said they couldnt prove he was a citizen, so they blocked his registration.

On Tuesday, Stricker was one of three Kansans who testified in a closely watched federal lawsuit challenging the law. Stricker and a handful of other Kansas voters are the plaintiffs in the case and contend the law violates a federal requirement that state agencies can only ask people the minimum amount of information necessary to assess their eligibility to vote when they give them the opportunity to register. To justify the law, Kansas officials have to prove that such a restrictive registration policy is justified by a substantial number of noncitizens on the voting rolls. In many ways, that is the same question at the heart of the national debate over voter fraud, which several studies have shown is not a widespread problem.