How key Republican senators are responding to Trump allies’ primary threats

DES MOINES, Iowa (AP) — From activists on the far right to Elon Musk, allies of President Donald Trump have been quick to threaten primary challengers for Republican senators who don’t back his Cabinet picks and legislative priorities.

In the case of Iowa’s Joni Ernst, conservatives threatened to run against her if she didn’t back Trump’s pick for defense secretary, Pete Hegseth — before she announced she would.

Louisiana’s Bill Cassidy, a doctor before entering politics, is being closely watched for how he will question Robert F. Kennedy Jr., Trump’s nominee for health secretary

South Carolina’s Lindsey Graham, a Trump confidant, has long been targeted by the far right in his state and was booed at a home-state rally during the 2024 presidential campaign.

The Associated Press talked to people connected to five senators who have been targeted online or by rivals in their states.

Here’s a look at each of their potential races and what they face:

Joni Ernst, Iowa

Ernst prompted criticism from the right after she initially stopped short of endorsing Hegseth, who was confirmed by the Senate on Friday. Ernst voted “yes.”

A retired Iowa National Guard lieutenant colonel and Iraq War veteran, Ernst is also a sexual assault survivor. After Trump announced Hegseth’s nomination, she said she hoped to discuss with him comments that he had made opposing women serving in combat roles, and about an allegation, which he denied and was not charged for, that he sexually assaulted a woman he met at a 2017 conference.

Hegseth, at Ernst’s suggestion, affirmed that that “every man and woman has opportunity to serve their country in uniform and to do so at any level as long as they are meeting the standards that are set forward.” Hegseth also said that if confirmed, he would appoint a senior-level official dedicated to sexual assault prevention and response.

Potential challengers to Ernst: Conservative media figure Steve Deace, who posted on Facebook in December that “I don’t want to be a Senator, but I am willing to primary her for the good of the cause.” Iowa Attorney General Brenna Bird wrote in a December opinion piece in Breitbart that some unnamed “D.C. politicians” thought “they can ignore the voices of their constituents and entertain smears” from news media outlets. That prompted speculation that Bird, who endorsed Trump before the 2024 Iowa caucuses, might challenge Ernst, who stayed neutral beforehand. Charlie Kirk of the conservative group Turning Point also called for Ernst to face a primary. An effort to boost Hegseth’s nomination led to Ernst’s office receiving thousands of calls.

Cause for concern: Neither Deace nor Bird has taken any public steps toward running. Some prominent social conservatives are bothered by Ernst’s joining with a dozen Republicans and the Senate’s Democratic majority in 2022 to support repealing the Defense of Marriage Act to recognize the validity of same-sex marriages. But she remains popular with Iowa’s power players.

“Anyone who says with a straight face that they are going to beat Joni Ernst in a primary today is kidding themselves,” said Luke Martz, an Iowa Republican consultant. “It would be a fool’s errand.”

Thom Tillis, North Carolina

Tillis angered some on the right for not immediately supporting Trump’s first pick for attorney general, former Florida Rep. Matt Gaetz. Though Gaetz withdrew from consideration, Tillis remains a frustration to some among North Carolina’s right wing, in part for voting to repeal the Defense of Marriage Act.

Potential challengers: Andy Nilsson, a onetime candidate for lieutenant governor, has filed paperwork to challenge Tillis. The retired businessman has called for a return to the Reagan-Bush Republican ethos, hardly an attack from the right. Tillis faced three Republican challengers in 2020, all posing as more conservative than him.

Cause for concern: Tillis has reason to expect a right-wing challenge. That faction helped lift former Lt. Gov. Mark Robinson to the 2024 nomination for governor last year. But North Carolina is expected to be among the most competitive states for Senate Republicans to hold in 2026. Roy Cooper, a Democrat who just finished two terms as governor, has not ruled out running for the seat. National Republicans are aware of the risks of nominating someone too far to the right. Cooper’s Democratic successor, Gov. Josh Stein, beat Robinson by nearly 15 percentage points in a state that Trump won by 3 points.

To that end, Trump’s team and Tillis have been working together behind the scenes, said former Gov. Pat McCrory, a fellow Republican.

“I anticipate there will be threats of challenging him from the right. But I also think he’ll deal with it as he has, with hard work and a record of accomplishment,” McCrory said. “I think the incoming administration sees that.”

“They also see he’s the best chance of keeping North Carolina red,” he added.

Bill Cassidy, Louisiana

Cassidy remains vulnerable in large part due to his vote to convict Trump after his second impeachment over the siege of the U.S. Capitol. “Our Constitution and our country is more important than any one person. I voted to convict President Trump because he is guilty,” Cassidy said in a statement after the February 2021 vote.

Cassidy, in his second term, has not yet announced whether he will seek a third. A gastroenterologist before he entered politics, Cassidy will be closely watched for how he votes on Kennedy, a longtime vaccine skeptic who has questioned medical consensus on several issues.

Potential challengers: Cassidy has already drawn a Republican challenger, state Treasurer John Fleming. Fleming, a former U.S. House member from northern Louisiana, has said Cassidy’s impeachment vote “failed” Louisiana. Former U.S. Rep. Garrett Graves of Baton Rouge is also a potential challenger, as is Blake Miguez, a state senator from New Iberia.

Louisiana last year did away with its 50-year tradition of “jungle primaries,” where candidates from all parties ran in the same contest in November. Cassidy would now run in a closed Republican primary that might be more difficult if he faces one strong Trump-aligned challenger.

Cause for concern: Cassidy’s vote to convict Trump remains a sticking point for Republicans in a state the president won with 60% last year. But Cassidy is viewed as having strong constituent relations and visibility in the state, political observers say.

“Aside from that vote, I think he’s considered a good senator, and good at constituent work,” said Ellen Carmichael, a Louisiana Republican consultant and president of Washington-based Lafayette Company. “The base is unhappy with the vote he cast. But I wouldn’t count him out.”

John Cornyn, Texas

Cornyn in the past has been criticized within his own party for being too willing to work with Democrats and has drawn boos at GOP conventions in Texas. Commentator Tucker Carlson and others have urged a primary challenge against him.

Last year, Cornyn told the Dallas Morning News that, “God willing,” he would seek reelection in 2026. According to federal filings, Cornyn had more than $3.5 million on hand in toward the end of 2024.

Potential challengers: Texas Attorney General Ken Paxton is one of the state’s most powerful Republicans and also suggested Cornyn should be primaried. Paxton was acquitted in a 2023 impeachment effort and fraud charges against him were dropped last year. Cornyn and Paxton have sniped at each other on X, with Paxton calling Cornyn “anti-Trump” and “anti-gun” and the senator firing back, “Hard to run from prison, Ken.”

Cause for concern: Brendan Steinhauser, a Republican strategist who has worked on Cornyn’s previous campaigns, noted that the senator remains undefeated in elections.

“He’s never taken a race for granted. I would expect him to work extremely hard and crisscross the state of Texas to earn every vote possible in this upcoming election, assuming he has a primary challenger,” Steinhauser said. “I think it’s important for him to show the ways that he has worked with President Trump to enact the conservative America First agenda, and I would expect that would be a big part of his campaign message in a potential upcoming primary.”

Lindsey Graham, South Carolina

Seeking his fifth term, Graham will likely face primary challenges — he always has. County-level Republican parties have censured him a number of times for his willingness to work on bipartisan deals. One such measure derided Graham’s “condescending attitude” to the party’s grassroots organizers.

He has even drawn boos at some events of the party faithful in his home state. That includes a July 2023 Trump rally in Pickens — in the county where Graham grew up — where objections from the crowd drowned out more than five minutes of his remarks. When he took the stage, Trump also elicited boos when he mentioned Graham’s name.

Graham has named a campaign leadership team, which says he has more than $15 million on hand, including nearly $1 million raised in the final quarter of 2024.

Potential challengers: Rep. Ralph Norman represents South Carolina’s 5th Congressional District south of Charlotte, North Carolina, and is a member of the House Freedom Caucus. Another possible opponent could be Adam Morgan, a former South Carolina legislator who lost a primary bid last year against another congressman, Rep. William Timmons.

Cause for concern: While he was highly critical of Trump in 2016 when they competed for the Republican nomination, Graham has backed Trump ever since his first administration, frequently serving as his golf partner and Capitol Hill surrogate. Trump has backed him in turn. When the crowd in Pickens booed Graham’s name, Trump said he was “going to have to work on these people” and added that Graham is “there when you need him.”

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Kinnard reported from Washington.

Thomas Beaumont And Meg Kinnard, The Associated Press