PORTSMOUTH, N.H. - With the first votes in the Republican presidential race fast approaching, a bullish Vivek Ramaswamy predicts he'll "shatter expectations" when the Jan.15 Iowa caucuses lead off the GOP nominating calendar.

And pointing to public opinion polls that suggest his support in the early voting states has flatlined in the mid to upper single digits while his unfavorability rating has edged up, the multi-millionaire biotech entrepreneur and first-time candidate argues the surveys are "way off the mark."

In a campaign trail interview with Fox News with five weeks to go until the Iowa caucuses, Ramaswamy reiterated he is "confident we’re going to do excellent in Iowa, that’s going to propel us forward when we come here to New Hampshire. And I think that’s going to carry us forward to the final phase of this race."

Ramaswamy, who has spent millions of his own money on his White House run, once again spotlighted his optimistic forecast hours after a new and reputable poll in Iowa suggested he stood at just five percent support among likely Republican presidential caucus-goers.

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NH man charged with threatening to kill GOP presidential candidate Vivek Ramaswamy

Republican presidential candidate Vivek Ramaswamy speaks at a campaign event at the Roundabout Diner in Portsmouth, New Hampshire on Dec. 11, 2023.  (Fox News - Paul Steinhauser)

The candidate noted that "history teaches us that where the polls stand in early December are not a good predictor necessarily of where things land ultimately. And I think we’re in for a shock that’s coming in the next few months."

"A lot of the people coming to our events, supporting me… they’re not polled. So I think the poll numbers are way off the mark and I think that works well for us," Ramaswamy argued.

He added that "there’s a lot of people who are libertarians, independents, young people, that are not in those polls…that are absolutely coming to the caucus for us."

And the Ramaswamy campaign pointed to their own internal numbers that suggest stronger support in Iowa than what the public surveys indicate.

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The 38-year-old Ramaswamy, who campaigns on an "America First 2.0" agenda, often highlights that "there are two America First candidates in this race. That’s Donald Trump and myself. Everybody else comes from an old-school vision of neo-conservatism that is long outdated, and that is not where our party or our base is."

Ramaswamy is the biggest supporter of the former president in the winnowing field of 2024 GOP White House hopefuls, and has repeatedly called Trump the "most successful president in our century."

Former President Donald Trump in IowA

Republican presidential candidate and former President Donald Trump speaks during a rally, Saturday, Nov. 18, 2023, in Fort Dodge, Iowa.  (AP Photo/Bryon Houlgrave)

But unfortunately for the candidate aiming to be Trump's heir apparent, the former president isn’t going anywhere. In fact, Trump remains the commanding front-runner in the GOP nomination race as he makes his third straight White House run.

Ramaswamy's rise in the polls in the late winter, spring and early summer was one of the biggest surprises in this cycle's GOP nomination race. And the candidate has put in the hours on the campaign trail, holding more events than his rivals in Iowa and New Hampshire – which holds the first primary in the Republican calendar and votes second after the Hawkeye State.

"I’m doing more events on the ground in Iowa right now than any other candidate and we’ve been here plenty as well," he showcased as he spoke with Fox News following a campaign stop in New Hampshire on Monday.

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Longtime Granite State-based Republican consultant Mike Dennehy told Fox News that Ramaswamy's put in the time in New Hampshire. I think that’s benefited him."

But Dennehy added that "there’s no doubt in my mind that he has a very limited ceiling because of his consistent support of Donald Trump…Why would someone want the Trump supporter when they can have Trump himself?"

New Hampshire man charged with threatening to kill GOP presidential candidate Vivek Ramaswamy

Republican presidential candidate Vivek Ramaswamy speaks at a campaign event at the Roundabout Diner in Portsmouth, New Hampshire on Dec. 11, 2023. A New Hampshire man was arrested for allegedly sending text messages threatening to kill Ramaswamy and other attendees at Monday's political event. (Fox News - Paul Steinhauser)

While some of the voters who showed up to see Ramaswamy at the campaign in Portsmouth, New Hampshire told Fox News and other news organizations they were likely to vote for him, plenty of others said they remained all-but-certain to support Trump.

Ramaswamy for months has vowed he'll pull off a "surprise" in Iowa. Asked whether that means he needs to win, or finish second, Ramaswamy answered, "it means meaningfully ahead of where the mainstream media narrative and the polling narrative is right now. And I think we’re going to accomplish that. I think we’re going to shatter expectations and that will propel us forward to the next phase of this race."

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The candidate has spent most of his time and resources in Iowa and New Hampshire, and less than impressive finishes in both states would likely all-but-sink his campaign. And in recent weeks he's broached the possibility on the campaign trail that his presidential bid won't succeed.

Asked if he would support Trump if his White House bid faltered, Ramaswamy told Fox News "if he’s the nominee, he’ll have my support."

But he quickly interjected that "I expect his full support if I’m the nominee."

And Ramaswamy added that "I’m not a plan B person. I’m a plan A person. I didn’t get to where I am in life by plotting out plan B. I’m sticking to Plan A and I think we’re going to succeed in getting there."

Get the latest updates from the 2024 campaign trail, exclusive interviews and more at our Fox News Digital election hub.