WICHITA, Kan. (AP) — The vice chairman of President Donald Trump's election fraud commission says he wants to change U.S. election law so states have an incentive to require proof of U.S. citizenship to register to vote, according to a deposition unsealed Thursday.

Kansas Secretary of State Kris Kobach, a leading advocate of tighter voting laws, gave the testimony in a deposition made public as part of a federal lawsuit filed by American Civil Liberties Union challenging a Kansas voter registration law that requires documents such as a birth certificate, U.S. passport or naturalization papers.

The deposition in August is the result of an ACLU court filing after Kobach was photographed holding a document with the words on one page facing out as he entered a meeting with then President-elect Donald Trump to talk about immigration. The ACLU asked a court to force Kobach to release the document. A federal judge said there was a pattern of Kobach misleading the court in that suit, fined him $1,000 and ordered him to submit to questioning under oath by the ACLU about that document and a proposed draft amendment to the National Voter Registration Act.

"To me, they really confirmed what we always suspected: that there is this ready-made plan to gut the core voting rights protections of federal law and Kobach has been lobbying Trump and his top team from day one to execute that scheme," said ACLU lawyer Orion Danjuma.

The photographed document Kobach took into his meeting with Trump was titled "Department of Homeland Security Kobach Strategic Plan for First 365 Days." It included the header "Stop aliens from voting."

At the deposition, Kobach said that he gave copies of the document to everyone at that meeting, and that the issue of noncitizen voting was discussed.

The purpose of that meeting was to discuss the possibility of Kobach becoming secretary of homeland security, which has a major say in immigration matters. In addition to Trump, others in the meeting included Reince Priebus, who subsequently became chief of staff; Steve Bannon, who became strategic adviser, Stephen Miller, who became a domestic policy adviser; and Jared Kushner, the president's son-in-law.

During his deposition, Kobach acknowledged he has talked about documentary proof of citizenship for voter registration with the members and staff of the election fraud commission.

Kobach also testified that GOP Rep. Steve King of Iowa has agreed to introduce legislation amending U.S. election law to allow states to impose proof-of-citizenship requirements if Kansas loses a federal lawsuit brought by the ACLU in Kansas.

The congressman's spokesman, John Kennedy, said in an email that King "believes it is an important policy to ensure that only citizens vote, and he hopes to follow up on this in the future."