Kevin Hern launches Senate bid for Markwayne Mullin’s Oklahoma seat

A member of the House GOP leadership is entering the open race for a Senate seat likely vacated by Sen. Markwayne Mullin, R-Okla., after being tapped to lead the Department of Homeland Security (DHS).

House GOP Policy Committee Chairman Kevin Hern, R-Okla., officially launches his Senate campaign Wednesday with the support of at least four Republicans in the upper chamber.

“The American dream is under threat from the radical left and RINO Republicans who oppose President Trump’s America First agenda and want to turn the United States into a third world country,” he says in his first campaign video.

“That’s why I’m running for the United States Senate – to ensure that President Trump has a loyal ally, a leader who stood by him when the RINOs turned their backs on him, who will fight against Democratic madness, keep the southern border secure, deport dangerous illegal immigrants, stand with law enforcement, and ensure economic affordability.”

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House GOP Policy Committee Chairman Kevin Hern is running for the Senate seat that will likely open in November after Sen. Markwayne Mullin is chosen to lead DHS. (Tom Williams/CQ-Roll Call, Inc. via Getty Images; Tom Williams/CQ-Roll Call, Inc. via Getty Images)

Hern, who grew up poor without indoor plumbing until his teens, found considerable wealth as a McDonald’s franchisee before running for Congress in 2018.

He is the first major Republican candidate to declare his intention to run for Mullin’s seat in November — and whoever wins the GOP primary in this deep red Midwestern state will likely be the favorite.

Mullin is expected to leave the Senate after being chosen by President Donald Trump to lead DHS following the firing of Kristi Noem. He faces a confirmation hearing later this month.

Traditionally, Senate vacancies are filled by the state’s governor to fill the remainder of the previous senator’s term. This person is also usually the favorite to win the seat in the following election cycle.

But in Oklahoma, the governor’s appointee must sign an affidavit swearing they will not run in the next election — which in this case will be in November, with Mullin’s term ending at the end of 2026.

Secretary of Homeland Security Kristi Noem delivers remarks during a working lunch at the “Shield of the Americas” summit at Trump National Doral in Miami, March 7, 2026. (Rebecca Blackwell/AFP via Getty Images)

It’s not yet clear how crowded the GOP primary for Mullin’s open seat will be. Rep. Stephanie Bice, R-Okla., previously said she was considering her own campaign but had made no final decisions.

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Hern, for his part, already has Trump agents on his team.

He recruited pollster Tony Fabrizio, closely linked to the president, as a senior adviser to his campaign.

Fabrizio said in a statement that Hern is in a “strong position” to win the seat, citing his “history of support for President Trump’s agenda, the trust he has built with Oklahoma voters, and his experience in public office and business.”

Meanwhile, Senate Majority Leader John Thune, R-S.D.’s, first goal is to quickly fill Mullin’s seat. He is expected to meet with Oklahoma Gov. Kevin Stitt, a common practice when an appointment needs to be made, this week, a close source told Fox News Digital.

It’s common for a governor to meet with the Senate leader to work on appointing a replacement, as is the case with Mullin, who is expected to begin his confirmation process in the upper chamber next week.

Oklahoma Governor Kevin Stitt briefs the media on a deadly tornado that ripped through Barnsdall in northeastern Oklahoma on May 7, 2024. (Brandon Bell/Getty Images)

Further down the line, Thune has no preference on who would replace Mullin, who is currently a member of his leadership team.

“You know, we obviously want to — we’re going to have to fill this seat for Markwayne here by the end of the month in the short term, and then the long term question will be decided by the voters of Oklahoma,” Thune said. “So whoever they decide to send us, we will be happy to receive it.”

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Still, Hern has already garnered support from a handful of senators, including Sen. Jim Banks, R-Ind., Bill Hagerty, R-Tenn., Rick Scott, R-Fla., and Ron Johnson, R-Wis.

Trump has set a March 31 deadline for Mullin to take over and Noem to step down, and it is expected to easily pass through the Senate Homeland Security and Governmental Affairs Committee. Whether Mullin will face obstacles in a full confirmation vote remains an open question.