President Biden has nominated a critic of the Trump administration’s immigration policies to run U.S. Immigration and Customs Enforcement, one of the federal government’s most polarizing agencies.

The White House announced that Biden’s pick for ICE director is Harris County, Tex., Sheriff Ed Gonzalez, a veteran law enforcement officer who transformed the sheriff’s office in the Houston metropolitan area from one of the agency’s staunchest allies into a reluctant partner.

Gonzalez withdrew his department from a voluntary federal program that for years helped to detain and deport immigrants, and has expressed concern that involving local law enforcement in civil deportation efforts “silences witnesses & victims” by making immigrants afraid to report crimes.

“I do not support #ICERaids that threaten to deport millions of undocumented immigrants, the vast majority of whom do not represent a threat to the U.S.,” Gonzalez said in a tweet in July 2019, amid reports of immigration roundups. “The focus should always be on clear & immediate safety threats. Not others who are not threats.”

Gonzalez’s position mirrors the Biden administration’s new policy to limit ICE arrests to recent border crossers or people who are threats to national security or convicted of aggravated felonies.

Gonzalez runs the third-largest sheriff’s office in the United States, with approximately 5,000 employees and a $571 million annual budget. If confirmed, he would take over a federal agency with more than 20,000 employees worldwide and an $8 billion-a-year budget.

Gonzalez’s nomination comes at a critical juncture for ICE, which a Pew Research Center survey found had a lower approval rating last year than the Internal Revenue Service.

ICE is best known for arresting and deporting people for civil immigration violations such as overstaying their visas or working without legal papers, and says it prioritizes the deportation of criminals. The agency also investigates crimes such as drug smuggling via its Homeland Security Investigations unit, which can target U.S. citizens.

But hundreds of sanctuary cities and towns have limited their cooperation with the agency, saying it sweeps up immigrants for minor offenses such as traffic stops. Some liberals have called for Biden to abolish ICE.

ICE is detaining more than 15,000 immigrants, among the lowest levels in years, and deportations from the interior of the United States plunged during the pandemic.

The Biden administration has signaled that it wishes to retool ICE, not abolish it, and Gonzalez is an example of how the agency’s relationships with local police can change.

Before Gonzalez’s election in 2016, Harris County was one of ICE’s most steadfast partners. Officials pioneered the federal agency’s Secure Communities program, which allows immigration officials to scan the fingerprints of anyone arrested for a crime to see if they are in the country illegally. And it enrolled in the 287(g) program, which tapped sheriff’s deputies to search county jails for people to deport. Gonzalez withdrew from that program in 2017.

He has said that police should stick to preventing crime, and ICE can enforce civil immigration laws.

“Diverting valuable law enforcement resources away from public safety threats would drive undocumented families further into the shadows & damage our community safety,” he said in a 2019 tweet.

Gonzalez has acknowledged that immigration agents still have access to his jail to detain immigrants, as required by Texas law.

If confirmed, Gonzalez will be charged with ensuring that immigration agents adhere to the Biden administration’s narrower enforcement priorities, a sharp reversal from President Donald Trump’s mandate to arrest anyone in the United States illegally.

Department of Homeland Security Secretary Alejandro Mayorkas, who oversees ICE, called Gonzalez “a strong choice” and urged the Senate to confirm him swiftly.

“With a distinguished career in law enforcement and public service, Sheriff Gonzalez is well-suited to lead ICE as the agency advances our public safety and homeland security mission,” Mayorkas said in a statement.

Harris County Commissioner Adrian Garcia, a Democrat and former county sheriff, said Gonzalez is a skilled communicator and reformer.

Some Harris County sheriff’s deputies have come under investigation for fatal shootings, including the April 14 shooting of a man “experiencing a mental health crisis” and wielding a knife, according to the sheriff’s department. But Garcia said Gonzalez embraces the difficult conversations that follow.

“He knows the value of research and considering public debate,” he said. “It’s never easy or simple, but I do believe Gonzalez’s sometimes quiet approach and engaging stakeholders on the back end and being transparent has enabled him to maintain the confidence of community leaders.”

Gonzalez describes himself as “a lifelong Houstonian,” and holds a bachelor’s degree in criminal justice from the University of Houston Downtown and a master’s degree from the University of St. Thomas.

He worked for 18 years in the Houston Police Department, rising from a civilian employee to police officer, homicide investigator and hostage negotiator, before retiring in 2009. He served three terms on the Houston City Council, chairing the Public Safety & Homeland Security Committee. He was elected sheriff in 2016 and reelected last year.