A Senate committee on Wednesday will consider Markwayne Mullin’s nomination to lead the Department of Homeland Security (DHS), which Democrats have forced into a partial shutdown until their demands for guardrails on immigration enforcement are met.

Donald Trump nominated Mullin, a first-term Republican senator from Oklahoma, as DHS secretary earlier this month, after the president ousted secretary Kristi Noem amid public blowback against the administration’s aggressive approach to its mass deportation agenda, which resulted in the killings of two US citizens by immigration agents in Minneapolis.

Mullin’s nomination collides with a standoff in Congress over funding for the department, which Democrats have refused to vote for unless the Trump administration and their Republican allies agree to a host of new guidelines on officers from agencies like Immigration and Customs Enforcement (ICE) and the border patrol, both of which are overseen by DHS. Among their demands are a ban on officers wearing masks and making random stops of people suspected of being in the country illegally, as well as the creation of a use of force policy.

Those issues are set to come up on Wednesday morning, when Mullin’s confirmation hearing begins before the Senate committee on homeland security and governmental affairs.

“I am grateful to President Trump for nominating me to lead the US Department of Homeland Security,” Mullin said on social media earlier this month.

“I look forward to earning the support of my colleagues in the Senate and carrying out president Trump’s mission alongside the department’s many capable agencies and the thousands of patriots who keep us safe every day.”

All signs point to a quick confirmation for Mullin, who was elected to the Senate in 2022 after serving five terms in the House of Representatives. Republicans have praised his nomination, and their control of the Senate gives them the numbers to push his appointment through even if Democrats oppose him.

The second-highest ranking Senate Republican, John Barrasso, called Mullin “a great senator” and said: “He will be an exceptional [homeland security] secretary and will work closely with president Trump to make America safer. As the whip, I will work to confirm him quickly.”

Democrats have been comparatively quiet about Mullin, with party leaders instead saying that their demands for reforms to immigration operations won’t change regardless of who leads DHS.

“This is a problem of policy, not personnel. The rot is deep. No one person can straighten this up until the president changes the whole agency, stops the violence, and reins in ICE,” the Senate minority leader, Chuck Schumer, said after Mullin’s nomination was announced.

Pennsylvania senator John Fetterman, who sits on the homeland security committee, is thus far the only Democrat in the chamber to endorse Mullin. “I’m not sure how many fellow Democrats will vote to support our colleague [senator Mullin] as the next DHS Secretary, but I am AYE,” he wrote on X.

The homeland security committee has scheduled a vote on his nomination for Thursday, after which it can be considered by the full Senate.

Republicans are likely to use the hearing to hone in on the impact of the DHS shutdown, which has led to employees of the coast guard, the Transportation Security Administration (TSA) and the Federal Emergency Management Agency (Fema) being furloughed or required to continue working without pay. In recent weeks, abnormally long lines have been reported at TSA checkpoints at several airports, and airline executives have publicly called for the shutdown to end.

The two parties nonetheless remain at loggerheads over how to do that. Democrats have proposed standalone bills to fund DHS agencies that are not involved in immigration enforcement operations while negotiations on their demands continue, but Republicans have blocked those, arguing it is essential to reopen the entire department.

The shutdown has not resulted in a halt to arrests and deportations, because those have been paid for by the One Big Beautiful Bill Act passed by Republicans last year.