What a difference a week makes.

As Pete Hegseth, President-elect Trump's defense secretary nominee, returns to Capitol Hill on Tuesday to meet with more Republican senators, his once apparently teetering nomination now seems to be on much firmer ground.

While Hegseth's confirmation is still far from a sure bet, a very public pronouncement of support from Trump, behind-the-scenes efforts by Vice President-elect Sen. JD Vance, and Hegseth's own determination seem to have resuscitated a nomination that appeared to be headed toward life support.

"We look forward to earning these confirmation votes," a confident Hegseth said Monday night in an interview on Fox News' "Hannity."

WHAT PETE HEGSETH TOLD FOX NEWS' SEAN HANNITY

In the wake of former Rep. Matt Gaetz,  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 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.

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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 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.

Trump's defense secretary nominee was interviewed hours after meeting a second time with Republican Sen. Joni Ernst of Iowa, the first female combat veteran elected to the Senate and a member of the Armed Services Committee, which will hold Hegseth's confirmation hearings.

Ernst, a conservative lawmaker first elected to the Senate in 2014, is considered a pivotal vote in the confirmation battle over Hegseth, who in the past has questioned the role of women in combat.

The senator is also a survivor of sexual assault who has a strong legislative record of addressing sexual assault and harassment in the military.

After meeting with Hegseth, Ernst wrote in a statement Monday that "as I support Pete through this process, I look forward to a fair hearing based on truth, not anonymous sources."

Ernst emphasized that "following our encouraging conversations, Pete committed to completing a full audit of the Pentagon and selecting a senior official who will uphold the roles and value of our servicemen and women – based on quality and standards, not quotas – and who will prioritize and strengthen my work to prevent sexual assault within the ranks."

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Hegseth, speaking with Fox News' Sean Hannity, noted that "it was a great meeting. People don't really know this. I've known Sen. Ernst for over 10 years. 

"You get into these meetings, and you listen to senators – it's an amazing advise and consent process – and you hear how thoughtful, serious, substantive they are on these key issues that pertain to our Defense Department," he continued. "And Joni Ernst is front and center on that. So to be able to have phone calls and meetings time and time again to talk over the issues is really, really important. The fact that she's willing to support me through this process means a lot."

Last week, after her first meeting with Hegseth, Ernst said in a social media post that she and Trump's defense secretary nominee had a "frank and thorough" conversation. 

A day later, when asked in an interview on Fox News' "America's Newsroom" if she wasn't ready to vote to confirm Hegseth, the senator replied, "I think you are right."

Even Republican Sen. Lindsey Graham of South Carolina, a longtime Trump ally in the Senate, was expressing serious concerns about Hegseth's nomination.

Fox News and other news organizations late last week reported that Trump was potentially considering nominating Florida Gov. Ron DeSantis as defense secretary as a possible replacement should Hegseth's nomination falter.

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But on Friday, Trump took to social media to praise Hegseth.

"Hegseth is doing very well. His support is strong and deep, much more so than the Fake News," the president-elect wrote. And he praised Hegseth in a high-profile network TV interview over this past weekend.

Vance, who remains a senator from Ohio until he steps down to assume the vice presidency, has been working behind the scenes to consolidate support for Hegseth among his Republican colleagues in the Senate.

"It's fair to say that JD has been Pete's biggest champion internally in Trump world and has spent a lot of time over the last two weeks helping shore up support for Pete among his colleagues in the Senate," a source in Vance's political orbit told Fox News.

Meanwhile, Trump's political team and allies – fueled by grassroots support for Hegseth – turned up the volume.

"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.

Donald Trump Jr., the president-elect's oldest son and MAGA powerhouse, took to social media to target 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!" Don Trump Jr. wrote in a social media post.

MAGA allies quickly targeted Ernst, with talk of a primary challenge when the senator faces re-election in 2026.

"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 Charlie Kirk, an influential conservative activist and radio and TV host who co-founded and steers Turning Point USA.

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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."

State Attorney General Brenna Bird, a top Trump supporter in last January's Iowa 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.

Deace, who supported DeSantis in the Iowa caucuses, said, "I am willing to primary her for the good of the cause if I'm assured I have Trump's support going in. Or I am willing to throw my support and network behind someone else President Trump prefers to primary Joni Ernst instead."

Also helping Hegseth is his defiance.

Hegseth told reporters on Thursday that "this will not be a process tried in the media. I don’t answer to anyone in this group. None of you, not to that camera at all. I answer to President Trump, who received 76 million votes on behalf... and a mandate for change. I answer to the 100 senators who are part of this process and those in the committee. And I answer to my Lord and Savior and my wife and my family."

And on Fox News' "Hannity," Hegseth charged that "the left is trying to turn this into a trial in the media, a show trial. And we're not going to let that happen."

Fox News' Emma Colton, Cameron Cawthorne, Tyler Olson, and Chad Pergram contributed to this story