Trump to replace Homeland Security chief Kristi Noem with Markwayne Mullin 

United States President Donald Trump has announced that he will replace Department of Homeland Security Secretary Kristi Noem with Republican Senator Markwayne Mullin.

In a social media post on Thursday, Trump explained that he had reassigned Noem to be a special envoy for a new security initiative focused on the Western Hemisphere, dubbed the “Shield of the Americas”.

The staffing change, he added, will take effect starting March 31. It marks the first major cabinet-level shake-up of Trump’s second term so far.

Trump praised Noem upon her departure from the cabinet-level post, writing that she “has served us well, and has had numerous and spectacular results (especially on the Border!)”

But Noem has played a prominent role in some of the administration’s most controversial immigration policies, and her tenure at the Department of Homeland Security (DHS) has spurred questions about government spending and conflicts of interest.

The announcement that she would be leaving her post comes a day after she faced a grilling from Democrats during congressional judiciary hearings this week, several of whom called for her resignation.

“DHS is supposed to be protecting our residents and upholding constitutional protections. But you’ve turned that on the head. You have actually turned the United States government against its own residents,” Representative Pramila Jayapal, a Democrat, said during Wednesday’s hearing.

“Yours is a case of failed leadership. Secretary, you need to resign, be fired or be impeached because you don’t have the right to lead this agency.”

The announcement of Noem’s removal also comes as DHS continues to weather a partial government shutdown.

Democrats have opposed approving new funding legislation for the department in response to several deadly shootings involving immigration agents under Noem’s leadership.

Those shootings were brought up again this week during Noem’s appearances before judiciary committees in the Senate and House of Representatives.

Democratic Representative Jamie Raskin, for instance, repeatedly accused Noem of launching a “smear campaign” against two US citizens shot dead during interactions with immigration agents: Renee Good and Alex Pretti.

“There have been three homicides in Minneapolis in 2026, and your agents committed two of them,” Raskin told Noem.

He also highlighted comments Noem made calling Good and Pretti “domestic terrorists“, despite evidence undercutting the administration’s depiction of the events leading to their deaths.

“Rather than work with state and local authorities to solve these homicides, you barred Minnesota’s investigators from the crime scenes,” Raskin said.

“It smells like a coverup and it makes me wonder who the real domestic terrorists are.”

Noem, formerly the Republican governor of South Dakota, has also been scrutinised for a $220m advertising campaign promoting border security.

The advertising campaign shows Noem riding a horse near Mount Rushmore, a well-known national memorial in Noem’s home state.

The news outlet ProPublica previously reported that a government contract for the campaign went to a Republican consulting firm with ties to senior DHS officials.

Noem has denied any wrongdoing, stating that the bidding process was “competitive” and that the contract was “all done correctly, all done legally”.

On Thursday, before announcing the staffing change, Trump denied any connection to the advertising campaign, telling the news service Reuters that he “never knew anything about it”.

Noem played a key role in the administration’s mass deportation push, and she has frequently used rhetoric that vilified immigrants as dangerous and violent.

Though DHS’s mandate is on domestic security, Noem has made several international trips over the last year, including visits to Ecuador in July and November.

Her replacement as DHS head, Mullin, has served as a US senator since 2023. He was a representative in the House for a decade before that, representing Oklahoma.

Trump highlighted his membership in the Cherokee Nation, writing that Mullin would be a “fantastic advocate for our incredible Tribal Communities” as DHS leader.

“Markwayne will work tirelessly to Keep our Border Secure, Stop Migrant Crime, Murderers, and other Criminals from illegally entering our Country, End the Scourge of Illegal Drugs and, MAKE AMERICA SAFE AGAIN,” Trump said on Thursday.