WASHINGTON — She’s an Iraq War combat veteran and sexual assault survivor who has advocated for years to improve how the military handles claims of sexual misconduct.

But when Sen. Joni Ernst, R-Iowa, appeared initially cool to the nomination of President-elect Donald Trump ‘s choice of Pete Hegseth to serve as defense secretary — a man who once said women should not serve in combat and who has himself been accused of sexual assault — she faced an onslaught of criticism from within her own party, including threats of a potential primary challenge in 2026.

“The American people spoke,” said Bob Vander Plaats, president and CEO of the Family Leader and a conservative activist in Ernst’s home state.

“When you sign up for this job, it’s a big boy and big girl job, and she’s feeling the pressure of people vocalizing their disappointment, their concern with how she’s handling this.”

The pressure campaign against Ernst, once a rising member of the GOP leadership, shows there is little room in Trump’s party for those who can’t get to yes on Hegseth or any of his other picks for his incoming administration

It underscores the power Trump is expected to wield on Capitol Hill in a second term and serves as a warning to other lawmakers who may be harboring their own concerns about other Trump selections, including Robert F. Kennedy Jr. for health secretary and Tulsi Gabbard to be director of national intelligence.

“If the king wants a different senator from Iowa, we’ll have one. If he doesn’t, we won’t,” said Iowa talk show host Steve Deace, suggesting on his show Monday that he would be willing to jump in against Ernst if Trump wanted a challenger. “I think someone’s got to be made an example out of, whether it’s Joni or someone else.”

Ernst’s allies say she can handle criticism

People close to Ernst, a retired Army National Guard lieutenant colonel, stress her mettle and say her eventual decision will depend on her assessment of Hegseth, a former “Fox & Friends Weekend” host and veteran, and nothing else.

“Has there been Twitter pressure? Sure. But Joni’s a combat veteran. She’s not easily pressured,” said David Kochel, an Iowa Republican strategist and longtime Ernst friend and adviser.

Ernst has worked steadily to shore up her relationship with Trump after declining to endorse him before the Iowa caucuses that kicked off this year’s campaign for the Republican presidential nomination. During a recent visit to Mar-a-Lago, Trump’s Florida club, she met with Trump and billionaire Elon Musk with ideas for their budget-slashing Department of Government Efficiency. She heads up a newly formed DOGE caucus in the Senate.

Trump has not tried personally to pressure Ernst to back Hegseth, according to a person familiar with their conversations who spoke on condition of anonymity to disclose them. And he has not targeted her — or any potential holdouts — publicly in social media posts.

He also hasn’t had to.

The response to Ernst built quickly, first in whispers following her initially cool remarks after meeting with Hegseth, then into a pile-on from powerful figures in the “Make America Great Again” movement.

Only about 2 in 10 Americans approve of Hegseth’s nomination, according to Associated Press-NORC Center for Public Affairs polling. About one-third of Republicans approve of him as a pick, and 16% disapprove. Another 1 in 10 Republicans, roughly, are neutral and say they neither approve nor disapprove.