One pro-Trump social media influencer wrote a viral post about Arizona Republican Kari Lake challenging Sen. Joni Ernst (R-IA) over the latter’s seeming reluctance to support Pete Hegseth’s nomination for secretary of defense.

Lake “was born and raised in Iowa,” Rogan O’Handley wrote. “What if she returns home to primary Joni Ernst in 2026 and take her Senate seat?”

Charlie Kirk, who, along with Elon Musk spearheaded much of Trump’s battleground state get-out-the-vote operation this year, also weighed in on Ernst and Hegseth.

RECESS APPOINTMENTS: HOW TRUMP HOPES TO SKIP SENATE CONFIRMATIONS AND FILL HIS CABINET

“People in Iowa have a well-funded primary challenger ready against her,” Kirk wrote on X, the Musk-owned social media platform formerly known as Twitter. “Her political career is in serious jeopardy.”

Donald Trump Jr. posted, “If you’re a GOP Senator who voted for Lloyd Austin but criticize Pete Hegseth then maybe you’re in the wrong political party!”

“Republicans are totally behind his agenda and are totally supportive of him putting the right people in place so he can solve the country’s problems,” Trump pollster John McLaughlin told RealClearPolitics. “If certain Republican senators side with the Democrats, they do so at their own peril.”

Axios reported that Trump allies have their eyes on Sen. Bill Cassidy (R-LA), the incoming chairman of the Senate Health, Education, Labor, and Pensions Committee, to see how he handles Robert F. Kennedy Jr.’s nomination to helm the Department of Health and Human Services. Cassidy voted to convict Trump in his second Senate impeachment trial. Rep. Clay Higgins (R-LA) has been discussed as a possible primary challenger.

Former Rep. Matt Gaetz of Florida has already withdrawn from consideration to be the next attorney general. The embattled Hegseth is meeting with GOP senators to try to save his nomination. This is before former Democrats Kennedy and Tulsi Gabbard or pro-union labor secretary nominee Rep. Lori Chavez-DeRemer (R-OR) are considered for their Cabinet slots.

There were reports that Trump might explore installing his Cabinet by recess appointments. Primary challengers against recalcitrant Republican senators is a more conventional political tool at his disposal. 

But that doesn’t mean primary challenges would be easy. Sen. Lisa Murkowski (R-AK) already weathered a conservative primary challenge during the Tea Party era when she was reelected to the Senate as a write-in candidate. She isn’t up for reelection again until 2028 in any event. Sen. Susan Collins (R-ME) is among the few members of her party who can win statewide. Republicans failed to unseat the Democratic incumbent representing the Maine congressional district Trump has now carried three times. Sen. Mitch McConnell (R-KY), who just stepped down from leadership, may not run again.

Those are the three Republican senators widely seen to be the least reliable votes for Trump’s nominees and broader agenda.

Trump-endorsed candidates did not always fare well in the 2022 midterm elections, with enough of them coming up short to prevent Republicans from capturing the Senate that year. He was more of an asset in 2024, sweeping all seven battleground states, but that wasn’t always enough to pull GOP Senate nominees across the finish line.

Republican Senate candidates lost in Michigan, Wisconsin, Arizona, and Nevada even as Trump won in all four states this November. Kari Lake has personally lost a Senate and gubernatorial race over the past two election cycles.

During the last big red wave in the 2010 midterm elections, Republicans failed to take control of the Senate even as they picked up 63 House seats. Despite massive down-ballot Democratic losses under former President Barack Obama, Republicans did not win a Senate majority until 2014, the Democrat’s second midterm election. Less competitive candidates emerging from GOP primaries, in some cases after challenging incumbents or establishment favorites, delayed McConnell from becoming majority leader.

Nevertheless, Trump has had some success in persuading his Senate GOP critics to leave Washington for greener pastures. Former Sens. Jeff Flake of Arizona and Bob Corker of Tennessee are gone. Retiring Sen. Mitt Romney (R-UT) will soon join them.

Many Never Trumpers inside and outside of government have effectively left the Republican Party over the eight years the former and future president has been its titular leader. 

But Republicans could face headwinds outside the party in the 2026 midterm elections. Trump is constitutionally ineligible to run for reelection, having already served a previous term. That means he needs to accomplish as much as he can early.

While some Trump allies say that is an argument for using drastic measures to ensure his appointees are confirmed, others contend he is in no shape for intraparty disharmony. 

Republicans will take control of the Senate on Jan. 3, and Trump will take office to start his second term 17 days later.