As President-elect Trump and his transition team steer his cabinet nominees through the landmines of the Senate confirmation process, top MAGA allies are joining the fight by putting pressure on GOP lawmakers who aren’t fully on board.

‘There will be no resource that we won’t use to go after those U.S. senators that vote against Donald Trump’s Cabinet picks or his other nominees,’ longtime Trump outside adviser Corey Lewandowski told Fox News this week.

Fueled by grassroots support for Trump and his nominees, the president-elect’s political team and allies are cranking up the volume.

Exhibit A: Republican Sen. Joni Ernst of Iowa.

Ernst, the first female combat veteran elected to the Senate, is considered a pivotal vote in the confirmation battle over Pete Hegseth, Trump’s nominee for defense secretary.

Hegseth, an Army National Guard officer who deployed to the wars in Afghanistan and Iraq and who until last month was a longtime Fox News host, has been the focus of a slew of media reports spotlighting a series of drinking and sexual misconduct allegations, as well as a report alleging he mismanaged a veterans nonprofit organization that he once led.

Hegseth has denied allegations that he mistreated women, but did reach a financial settlement with an accuser from a 2017 incident to avoid a lawsuit. He has vowed that he won’t drink ‘a drop of alcohol’ if confirmed as defense secretary.

Ernst, a member of the Armed Services Committee, which will hold Hegseth’s confirmation hearings, took plenty of incoming fire after last week publicly expressing hesitance over Hegseth’s nomination.

While Trump publicly praised Hegseth late last week, as the nomination appeared to be teetering, top allies of the president-elect took aim at Ernst, who is up for re-election in 2026 in red-state Iowa.

Donald Trump Jr., the president-elect’s oldest son and MAGA powerhouse, took to social media to target Ernst and other potentially wavering Republican senators.

‘If you’re a GOP Senator who voted for Lloyd Austin [President Biden’s defense secretary], but criticize @PeteHegseth, then maybe you’re in the wrong political party!’ he posted.

Top MAGA ally Charlie Kirk quickly took aim at Ernst with talk of supporting a primary challenger to her.

‘This is the red line. This is not a joke.… The funding is already being put together. Donors are calling like crazy. Primaries are going to be launched,’ said Kirk, an influential conservative activist and radio and TV host who co-founded and steers Turning Point USA.

Kirk, on his radio program, warned that ‘if you support the president’s agenda, you’re good. You’re marked safe from a primary. You go up against Pete Hegseth, the president, repeatedly, then don’t be surprised, Joni Ernst, if all of a sudden you have a primary challenge in Iowa.’

Iowa Attorney General Brenna Bird, a top Trump supporter in last January’s first-in-the-nation presidential caucuses, wrote a column on Breitbart urging Hegseth’s confirmation.

While she didn’t mention Ernst by name, Bird took aim at ‘D.C. politicians’ who ‘think they can ignore the voices of their constituents and entertain smears from the same outlets that have pushed out lies for years.’

And longtime Iowa-based conservative commentator and media personality Steve Deace took to social media and used his radio program to highlight that he would consider launching a primary challenge against Ernst.

Ernst, who stayed neutral in the Iowa caucuses before endorsing Trump later in the GOP presidential primary calendar, may have gotten the message.

After meeting earlier this week for a second time with Hegseth, Ernst said in a statement that her meeting was ‘encouraging’ and that she would ‘support Pete through this process.’

But Ernst’s office told Fox News that ‘the senator has consistently followed the process, which she has said since the beginning, and doing her job as a United States senator.’

It’s not just Ernst who has faced the fire from Trump allies and MAGA world.

Sen. Bill Cassidy of Louisiana, one of four remaining GOP senators who voted in the 2021 Trump impeachment trial to convict him, is also up for re-election in 2026 in a reliably red state. Cassidy is now facing a formal primary challenge from Louisiana Treasurer John Fleming, a senior adviser in the first Trump administration.

Sen. Mike Rounds, another Republican up for re-election in two years in GOP-dominated South Dakota, has also been blasted by Kirk, as well as by top Trump ally and billionaire Elon Musk.

And staunch Trump supporter Sen. Tommy Tuberville of Alabama had a warning for Republican Senate colleagues who may oppose the president-elect’s nominees.

‘Republicans: If you’re not on the team, get out of the way,’ he told FOX Business.

Whether these early threats from Trump allies turn into actual primary challenges in the next midterm elections remains to be seen. And ousting a senator is no easy feat. It’s been a dozen years since an incumbent senator was defeated during a primary challenge.

But Trump’s team and allies are playing hardball in the wake of former Rep. Matt Gaetz, R-Fla., the president-elect’s first attorney general nominee, ending his confirmation bid amid controversy.

There has been a full-court press by Trump’s political orbit to bolster Hegseth — in order to protect him and some of the president-elect’s other controversial Cabinet picks.

‘If Trump world allowed a couple of establishment senators to veto a second nominee, it would have led to a feeding frenzy on Trump’s other nominees, and so the thinking in Trump world was we have to defend Pete not just for the sake of defending Pete, but also for the sake of defending our other nominees,’ a longtime Trump world adviser, who asked to remain anonymous to speak more freely, told Fox News.

Fox News’ Emma Colton, Cameron Cawthorne, Julia Johnson, Tyler Olson and Chad Pergram contributed to this report.