J. Scott Applewhite, Associated Press

Rep. Bennie Thompson, Mississippi’s lone Democrat in Congress, is poised to become one of the most influential members of the U.S. House and a key player in House Democrats’ plan to serve as a check on President Donald Trump’s immigration policies.

Democrats’ regaining a majority in the House earlier this month helped cement Thompson’s clout. Thompson, currently the ranking member of the House Committee on Homeland Security, is likely to ascend to the chairmanship he previously held.

Thompson served as chairman of the committee between 2007 and 2011, when Democrats last held control of Congress. To put Thompson’s seniority into further perspective, he is one of just four Democrats who chaired a committee the last time the party held power and remains in office today.

As ranking member, Thompson has been a vocal critic of the Trump administration’s tack on immigration and other homeland security issues. As chairman, the role puts Thompson in a key position to look into how immigration policies are being carried out under Trump’s presidency.

Earlier this month, Thompson accused Trump of playing on fears of Central American migrants walking toward the U.S. border to motivate Republican voters.

“The President’s desperate attempts to militarize our southern border and tease out unconstitutional immigration policy are nothing more than political stunts and must be called out as such,” Thompson said in a press release. “A week before the midterm elections, it is clear President Trump wants nothing more than to change the narrative and incite hatred and fear in his political base.”

House Democrats aim to conduct hearings on some of the president’s most controversial immigration policies in the coming year, including the administration’s policy to criminally prosecute all border-crossers and its decision to end the Deferred Action for Childhood Arrivals program, news outlets have reported.

While legislation concerning immigration policy will start in the House Judiciary Committee, Thompson’s committee considers legislation related to domestic security and has oversight over the Department of Homeland Security, whose subagencies include U.S. Immigration and Customs Enforcement (ICE), Transportation Security Administration, Federal Emergency Management Agency, U.S. Customs and Border Protection and U.S. Citizenship and Immigration Services.

Thompson could perform regular audits of agency spending and internal accountability, said Ur Jaddou, director of the DHS Watch, a project of immigration reform group America’s Voice.

“The Republicans failed to do really any substantive review, so this is the opportunity,” Jaddou added.

Last year, after a white supremacist rally in Charlottesville, Va., Thompson expressed concern about the need for for stable leadership and resources for a kep counter-terrorism office that monitors domestic terrorists.

“You know the Ku Klux Klan were domestic terrorists. They carried out terroristic activities from the beginning even though they say they’re Christians or even patriots,” Thompson told Mississippi Today at the time.

Thompson could also look into subcontracts between ICE and private prison operators, Jaddou said. ICE spends over $2 billion a year on immigrant detention, and federal inspections have called into question the conditions, including staffing and medical care, at such facilities.

“That could take up all his time,” Jaddou said. “If he wanted to.”

Two of the nation’s largest private prison operators, both of which do business in Mississippi, have given Thompson campaign donations over the last five election cycles.

For election years 2010 and 2012, Thompson received $1,500 each cycle from CoreCivic, which runs the Tallahatchie County Correctional Facility in Tutwiler. The Tallahatchie facility began housing immigrant detainees over the summer.

GEO Group also donated $2,500 this year to Thompson’s campaign; in 2016, GEO’s PAC reported $5,000 in campaign contributions; in 2010, they gave $2,000.

Cathi Tactaquin, executive director of the National Network for Immigrant and Refugee Rights, hopes that in addressing immigration as an issue, Democrats will push back on the funding Trump is seeking to build a wall at the U.S.-Mexico border and hold fair hearings that acknowledge that border crossings have actually declined over the last decade.

Local and national immigrants’ rights groups characterize Thompson as committed to addressing issues prevalent in immigrant communities.

That work of building relationships between immigrant communities, civil rights groups and groups in African American communities is particularly important in states like Mississippi, where “there’s also not strong labor protections – there’s a history of racism, a history of disenfranchisement,” Tactaquin said.

“He’s always been a good representative to stand up on immigration issues especially as they intersect with national security,” Tactaquin said. “We’re looking forward to him playing a leading role in the next Congress.”

“His chairmanship is more than welcome,” said Bill Chandler, the executive director of the Jackson-based Mississippi Immigrants Rights Alliance. “Being in Mississippi, we know him very well and we know he has an immense amount of integrity and certainly is committed to human rights. So we’re excited about that prospect.”