Next week, Kansas Secretary of State Kris Kobach will go to federal court to defend a voting restriction that he has for years tried to implement in his state.

To help Kobach make his case, he’ll be calling on a former member of his now-defunct voter fraud commission, an anti-immigration hardliner, and a professor whose controversial study was used by the White House to justify President Trump’s false claim that “millions” voted illegally in 2016.

At issue in the case is a 2011 Kansas law, championed by Kobach, requiring that people registering to vote show documentary proof of citizenship. Voting rights advocates say the requirement disproportionately hurts minorities and low income voters, and violates federal voting law.

Several federal court rulings have blocked the law temporarily. Starting Tuesday, an ACLU lawsuit challenging the measure will go to full trial in Kansas City, Kansas.

A ruling in Kobach’s favor could open the doors for other states to impose similar laws. Arizona, Georgia and Alabama have all passed proof of citizenship laws for voter registration, though they have been blocked by courts from enforcing them. Kobach disclosed last year in a deposition that he has spoken with Rep. Steve King (R-IA) about introducing federal legislation making it easier for states to impose proof of citizenship laws.

Here’s a preview of who is expected to take the witness stand for the defense and what they might say.

Hans von Spakovsky

Von Spakovsky is a fellow at the conservative Heritage Foundation, and, like Kobach, has been a leader of the campaign to exaggerate the threat of voter fraud. Most recently, von Spakovsky served on Trump’s “election integrity” commission, which was shut down in January due to mounting legal troubles. Kobach was its vice chair and de facto leader.

Before being named to the commission, von Spakovsky sent an email that was forwarded to Attorney General Jeff Sessions decrying the move to put Democrats and even “mainstream Republican officials and/or academics” on the commission. Doing so, von Spakovsky wrote, would “guarantee” the panel’s “abject failure.”

Von Spakovsky made a name for himself serving in President George W. Bush’s Justice Department, where he overrode career officials in green-lighting Georgia’s voter ID law and a Texas redistricting plan.

When Arizona — in an effort backed by Kobach — was trying to enforce its own proof-of-citizenship voter registration requirement, von Spakovsky pressured the U.S. Elections Assistance Commission to let the state include the requirement on its federal registration form.

In 2005, von Sapakovsky received a recess nomination to the Federal Election Commission. But Democrats refused to hold a vote on his permanent nomination, citing his record at DOJ, and von Spakovsky ultimately withdrew from contention.

At an earlier stage of the Kansas case, the challengers sought to prevent von Spakovsky from offering testimony on a survey commissioned by Kansas on the citizenship requirement. The survey was conducted without the involvement of Von Spakovsky, who has admitted he isn’t a social scientist.

“It is clear that von Spakovsky is not qualified to testify as an expert about this survey,” U.S. District Judge Julie A. Robinson, said in an order that limited the scope of von Spakovsky’s testimony.

Steven Camarota

Camarota is the research director at the far-right Center for Immigration Studies, which has been designated a hate group by the Southern Poverty Law Center. The think tank is a favorite of anti-immigration advocates for its oft-debunked research claiming immigrants drive crime and hurt the economy.

Among Center for Immigration Studies’ founders was John Tanton, a proponent of eugenics, who has said that the United States needed to maintain its “European-American majority” in order to persist.

But Camarota isn’t being asked to weigh in on the immigration aspects of the case. Instead, according to court documents, he’s set to testify that there is “no evidence that the proof of citizenship requirement adversely impacts the registration or participation rates of U.S. citizens in Kansas.”

The ACLU wanted Camarota’s testimony excluded earlier in the case, too, on the basis that he “is an immigration researcher who has no expertise in the area of voting.”

In response, Kobach’s office pointed to Camarota’s work on a contract with the Census.

“[W]hile it may be true that Dr. Camarota lacks published peer-reviewed research about voting, the analysis he performed to reach his conclusions in this case, namely analyzing Census data and administrative data, is derived from his relevant experience using Census Bureau data to analyze trends in registration and voting,” Kobach’s court filing said.

Jesse Richman

Richman, a professor at Old Dominion University, is slated to testify about the “number of noncitizens that have registered or attempted to register to vote in Kansas,” according to a court document.

Richman’s work has attracted widespread scrutiny in the past. An op-ed he wrote for the Washington Post claiming that non-citizen voting may have been responsible for swinging North Carolina to Barack Obama in 2008 earned three separate rebuttals in the Post alone.

That didn’t stop spokespeople for President Trump from touting the study as justifying his claim that three to five million people voted illegally in 2016. Richman distanced himself from that conclusion, saying that even his maximalist estimate — that up to 800,000 non-citizens may have voted in 2008 — is well short, if extrapolated to 2016, of the 2.8 million votes needed to have tipped the popular vote to Hillary Clinton.

A different Richman study, conducted for the state of Kansas, has been criticized for extrapolating from a survey with a sample size of 37 non-citizens to conclude that an estimated 16.5 percent of non-citizens in the state have registered to vote or attempted to do so*. Another one of Richman’s analyses is based on a sample size of 14 possible non-citizens , of which he found four potential voters.

Not surprisingly, the ACLU challenged his testimony at an earlier stage in the case as well. In doing so, the challengers pointed to an article written by the widely respected Harvard professor Stephen Ansolabehere, who developed the study from which many of Richman’s findings are derived. Ansolabehere accused Richman of presenting “a biased estimate of the rate at which non-citizens voted in recent elections.

* This sentence has been edited to more accurately describe the findings of the study at issue.

Illustration by Christine Frapech- Getty Images/Douglas Graham/The Washington Post/Scott J. Ferrell.