What you need to know about Sen. Markwayne Mullin, Trump’s new pick to lead DHS : NPR

President Donald Trump announced Thursday that he has chosen Sen. Markwayne Mullin, R-Okla., to be the next Secretary of Homeland Security.

If confirmed, Mullin would replace Kristi Noem, who has led the agency through a broad and controversial crackdown on immigration in the country. Trump announced the decision in a post on his social media site, Truth Social.

“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. Markwayne will make a spectacular Secretary of Homeland Security,” Trump wrote.

In a statement posted to social media, Mullin said serving Oklahoma in Congress “has been the greatest honor and privilege,” and he expressed appreciation for the nomination.

“President Trump ran on restoring law and order, and he quickly delivered the most secure U.S. border in American history. I look forward to supporting @POTUS
‘ mission to safeguard the American people and defend the homeland,” Mullin said.

Mullin is a relatively new face in the senate who has established himself as a close ally of Trump and a vocal defender of the administration’s immigration enforcement tactics.

Mullin has served in Congress since 2013

• Mullin was first elected to the House in 2012 and was sworn in the following January.
• A decade later he won a special election to fulfill the term of former Sen. James Inhofe, a fellow Republican who resigned due to health issues.
• Mullin is an enrolled member of the Cherokee nation. He is the first tribal citizen in the Senate since Ben Nighthorse Campbell left in 2005.
• Mullin has been a reliable defender of President Trump in Congress, including just this week, backing the president’s decision to launch strikes against Iran.
• Mullin serves on several committees, including Appropriations, Armed Services, Indian Affairs and Health, Education, Labor and Pensions.
• In his role on the Appropriations Committee, he helps write and negotiate federal funding, including the ongoing talks to fund DHS, the agency he has been tapped to lead.
• DHS has been operating without annual appropriations funding since February 14.
• Mullin has frequently defended President Trump’s approach to immigration enforcement.

Mullin was previously a contractor, a talk show host and a mixed martial arts fighter

Trump picked Mullin, but he still needs to be confirmed by the Senate.

• President Trump says Mullin will start in the new role on March 31st. 
• The Senate will set the confirmation schedule.
• Mullin will need to appear before the Senate Committee on Homeland Security and Governmental Affairs.
• Mullin has clashed with the committee’s chairman, Rand Paul, R-Ky., in the past, according to news reports.
• Mullin told reporters on Thursday that he was informed about the selection right before Trump made it public. “The president and I have already talked, the statement came out but we’re going to get on the same page and do what we need to do,” he told reporters at the Capitol.

What will happen to Mullin’s seat in the Senate?

• Mullin was up for reelection this year.
• Oklahoma law says the governor will pick a replacement to serve through Jan. 2027.
• There’s still time for candidates to declare to run for the full term.