U.S. Rep. Pramila Jayapal (D-WA) said Thursday that if Democrats take control of the U.S. House of Representatives in November’s midterm elections, they would hold hearings to draw public attention to Trump administration officials with well-documented connections to extremists, like White House advisor Stephen Miller.

“I don’t think the public understands” Miller’s role in the Trump administration, Jayapal said. A Democratic House majority, she said, would seek to remedy that by holding hearings focused on administration officials with ties to hate groups, including the white supremacist movement.

Jayapal joined an expert on hate groups and an immigration advocate during a Thursday press call to highlight Miller’s “white supremacist” bona fides, in response to reports that Miller conceived of the Trump administration’s “zero tolerance” immigration policy, which tears apart families at the U.S.-Mexico border by criminalizing even asylum seekers. President Trump has since issued an executive order claiming to end family separation, though the U.S. Department of Justice says it will continue to prosecute migrant parents who come to the United States without documentation. 

Immigration advocates on Thursday’s call said Miller’s influence on the national immigration debate doesn’t stop with Trump administration policy, as his apparent white supremacist priorities are reflected in parts of the Republican immigration bills being considered this week on Capitol Hill. This includes capping refugee admissions and ending the visa diversity lottery, which awards 50,000 green cards a year, mostly to African recipients, the Washington Post reports. Almost seven in ten Black immigrants come to the US via sponsorship by relatives or through the diversity visa lottery, according to a Black Alliance for Just Immigration report. 

The Republican effort to severely curb immigration of Black and brown people while favoring white, wealthier immigrants is at the heart of Miller’s radical stance on immigration, said Patrice Lawrence, national policy and advocacy director at the UndocuBlack Network, which advocates for undocumented Black people.

“There’s no reason to implement these policies except to advance [Miller’s] xenophobic … white supremacist agenda,” Lawrence said.

Jayapal recently sat with 174 detained immigrant women, almost all of them seeking asylum in the United States, as they recounted the lies they were told to separate them from their children.

It’s time to step over here and take your photo, immigration officials told them. It’s time for your hearing. Suddenly they were away from their little girls and boys, sometimes separated by nothing but a wall in a detention facility, Jayapal said.

“They could hear their kids in the next room, crying for them,” while some mothers had no idea where their children had been taken, she said. “All of them wept when they talked about this.”

That agony—the pain of losing a child to a chaotic bureaucracy instructed to rip families apart—was “the creation of Stephen Miller,” Jayapal said during a Thursday press call. “Miller is a guy who has devoted his life to anti-immigrant … white supremacist policies,” she said, reiterating her call for Trump to fire Miller, who described the policy of taking immigrant children from their parents as a “simple decision.”

Heidi Beirich, head of the Southern Poverty Law Center’s Intelligence Project, offered a laundry list of Miller’s links to anti-immigrant and anti-Muslim hate groups, including his work with David Horowitz’s Freedom Center, which spreads misinformation about Islam. Miller in 2017 helped devise the administration’s Muslim ban. Miller’s connections with white supremacists and hate groups have been largely ignored in coverage of his key role in the Trump administration.

“It’s not as if Miller’s ideas came out of a vacuum,” Beirich said. “There’s a really ugly movement that … is now controlling [federal] policies.”

Beirich pointed to Miller’s longtime relationship with white supremacist leader Richard Spencer, who led fellow white supremacists and neo-Nazis at the August 2017 hate rally in Charlottesville, Virginia, where a white supremacist ran his car into a group of counter-protesters, killing activist Heather Heyer. After Trump’s 2016 election victory, Spencer led a raucous cheer, “Hail Trump, hail our people, hail victory!”

Miller has long denied his relationship with Spencer during their time at Duke University’s Conservative Union—a denial refuted by Peter Laufer, an independent journalist and University of Oregon professor who met Miller and Spencer at a debate on U.S. immigration policy in 2007. Laufer in Thursday’s press call described having a drink with Miller and Spencer, and “ducking out” when he became put off by the conversation. Laufer then exchanged emails with Miller and Spencer, seeking reimbursement for costs associated with traveling to the immigration debate. He shared his email exchange with Electronic Intifada in February 2017.

“This was not a one-off relationship,” Laufer said Thursday. “It’s fatuous to say [Miller and Spencer] were merely passing in the night.”

Spencer has spoken openly of his relationship with the man shaping Trump’s immigration policy. “I knew him very well when I was at Duke,” Spencer told Mother Jones in October 2016. “But I am kind of glad no one’s talked about this because I don’t want to harm Trump.”