After a tenure marked by controversy and a contentious week of Congressional hearings, secretary Kristi Noem is out as head of the Department of Homeland Security.

President Donald Trump announced in a Truth Social post on Thursday that Noem would be replaced by Senator Markwayne Mullin of Oklahoma, a staunch Trump ally and immigration hard-liner. “The current Secretary, Kristi Noem, who has served us well, and has had numerous and spectacular results (especially on the Border!), will be moving to be Special Envoy for The Shield of the Americas, our new Security Initiative in the Western Hemisphere we are announcing on Saturday in Doral, Florida,” Trump wrote. “I thank Kristi for her service at ‘Homeland.’”

DHS did not immediately respond to a request for comment.

The agencies under DHS include Immigration and Customs Enforcement, US Customs and Border Protection, the Cybersecurity and Infrastructure Security Agency, the Federal Emergency Management Agency, US Citizenship and Immigration Services, the US Coast Guard, and others. It’s a sprawling network whose vast responsibilities and rapidly expanding budget have put it at the center of the Trump administration’s radical overhaul of immigration and border policy.

Speculation has swirled around Noem’s departure for months. Critics have assailed DHS’s aggressive immigration enforcement tactics, while Noem and figures like White House border czar Tom Homan have reportedly been at odds over how to execute the administration’s mass deportation agenda, with Noem and senior adviser Corey Lewandowski said to have emphasized sheer numbers of arrests and deportations above other considerations.

The relationship between Noem and Lewandowski has itself been a subject of controversy, with CNN reporting that a September meeting between the two and President Trump grew “contentious.” Last month, The Wall Street Journal reported that Lewandowski attempted to fire a pilot during a flight for failing to bring Noem’s blanket from one plane to another during a transfer.

The ousted secretary faced mounting scrutiny over the deaths of US citizens during federal operations in Minneapolis, including the killings of Renee Good and Alex Pretti by federal agents under Noem’s employ. In both cases, Noem publicly labeled the deceased “domestic terrorists,” framing echoed by Trump and other key administration officials. Video evidence, witness testimony, and an independent autopsy contradicted the agency’s claims, including early assertions that Pretti brandished a firearm.

Scrutiny of Noem’s tenure extends beyond the fatal shootings in Minneapolis to a broader pattern of aggressive enforcement tactics, warrantless raids, and mass detention camps. A secretive policy directive issued in May 2025, first reported by the Associated Press, authorized ICE agents to forcibly enter private residences without a judicial warrant. The memo, signed by acting ICE director Todd Lyons, instructed agents to rely solely on an administrative removal document to bypass Fourth Amendment requirements. The policy led to multiple documented instances of federal agents entering the wrong homes, including a January raid in Minnesota where agents removed a US citizen at gunpoint with no legitimate reason.

A record 53 people died in ICE or CBP custody last year, according to House Democrats on the Committee on Homeland Security. Concurrently, Noem has initiated a $38 billion procurement effort to buy and refurbish up to 24 warehouses across the country, aimed at converting them into mass detention camps for people awaiting deportation.

Noem’s tenure has led to controversy at other DHS agencies as well. Her insistence on approving any contracts or grants over $100,000 at the department have caused particular strain at FEMA, which has experienced a massive backlog of funding that has slowed normal processes at the agency. A report issued from Senate Democrats on Wednesday found that Noem’s vetting process at FEMA has caused more than 1,000 contracts, grants, and awards to be held up. Multiple FEMA employees have told WIRED that this process has made the agency less ready to respond to disasters and threats.