South Carolina Sen. Tim Scott is doubling down on Iowa, ramping up his visits to the state as he looks to prove he can compete in the battle to mount the strongest primary challenge to GOP front-runner former President Donald Trump.

CNN obtained a recording of a Thursday call with donors that featured Scott and senior campaign officials, during which Scott said the campaign has "not yet launched a national campaign." Instead, they are focusing on Iowa and will continue that strategy "for the next several weeks and couple months."

"We are making progress in the great state of Iowa. We're going to continue to do so. We have not yet launched a national campaign, we have launched a successful Iowa strategy," Scott told donors. "We'll continue to play that out for the next several weeks and couple of months."

The call came just days after the super PAC supporting his campaign canceled the remainder of its TV and digital ad reservations

Scott campaign senior adviser Zac Moffatt said on the call that the campaign plans to bolster Iowa ground game with additional staffing and increased visits to the state in the coming weeks.

"You're gonna see us put more and more of an emphasis, because we know that we need to do well in Iowa to have a springboard to everything else. So you'll get to see us put more and more of an emphasis with our resources and our staffing to ensure that we're in Iowa fighting every single day for every vote we can," Moffatt said. "And the reason we're doing that is that we feel like Iowa is still not only not settled, but there's a massive opportunity there."

The day after the call, Scott embarked on a five-day bus tour of Iowa, even as his path to the nomination appears murkier than ever. Earlier this week, Trust in the Mission PAC, the super PAC supporting Scott's campaign, announced it is canceling the remainder of its $40 million in TV and digital ad reservations, citing the challenges of "breaking through" to voters. The announcement came a day after federal filings showed the Scott campaign spent $12.4 million during the third quarter but only raised $4.6 million in that same time period, putting a dent in his once-formidable advantage in cash reserves.

Scott told CNN's Abby Phillip on Thursday he supports the decision by the super PAC to pull its ad buys and dismissed questions about the health of his campaign.

"I don't run the super PAC. So I can't tell you exactly what that memo meant, but what I can tell you is that it focuses on is reserving our resources until later in the campaign so that as we get close to the January 15, date of the Iowa caucus, we have the resources to spend effectively," Scott said. "Breaking through this current news cycle seems to be impossible. So any alternative to the former president will not have actual opportunity to showcase why they should be the alternative."

When asked if he's considering dropping out of the race given the context laid out in the memo, Scott said he plans to keep running.

"Oh, of course not," Scott said. "We believe that America's ready for an optimistic positive messenger who is anchored in consistently conservative values."

Scott's efforts to establish his viability are compounded further complicated by a struggle to make up ground in the polls in comparison to rivals like Florida Gov. Ron DeSantis and former South Carolina Gov. Nikki Haley. In a national Fox News poll of potential Republican primary voters released last week, Scott earned 1% support. Scott received 3% in a September Fox survey. Scott has not yet met the polling threshold to qualify for the November debate, which mandates candidates receive 4% support in two national polls or one national poll and two early state polls. He has surpassed the donor requirements set by the Republican party, a campaign spokesperson told CNN.

A South Carolina-based Republican strategist supporting Scott's campaign said the cancellation by the PAC gives the South Carolina senator a chance to take stock of the primary landscape.

"I think the memo on Monday, it was certainly a chance to sort of reset, take a deep breath and get ready for this final lap," the strategist said.

Scott's Iowa bus tour is part of an effort by the campaign to raise his popularity in the state, with the hope that a strong showing in the caucuses in January can spark some momentum and propel him into viability. The visit to the Hawkeye State for this weekend's tour will be his third trip there in as many weeks, and the trips are supplemented by a bevy of TV ads from his campaign targeting Iowa voters. As of Friday, Scott's campaign has spent $11.6 million on TV ads, more than any other campaign so far. More than half of those ad buys have been in Iowa, according to data from the ad tracking firm AdImpact.

Scott often leans into his Christian faith and his background to appeal to the significant evangelical coalition among Iowa Republicans, frequently quoting scripture at campaign stops.

Scott campaign pollster Erik Iverson presented internal polling data to donors on Thursday's call to support the campaign's focus on evangelical voters, whose support he said remains up for grabs.

"Traditionally in Iowa, that evangelical lane plays a very outsized level of importance," Iverson said. "Sort of remarkably, that lane is completely unfilled right now. It's completely wide open."

On the call with donors Thursday, Moffatt said he believes the campaign has enough time to pick up support as more voters make up their minds.

"If you look at the history of prior presidential races, moderates jump out to an early lead, they consolidate quickly and they get all this hope and change that's coming into September, October, and then they crash into the winter," Moffat said on the call. "I will say, winter is coming as conservatives and as the primary electorate starts to pay attention. You're going to see big moves, and it always ends badly for the people who started early who haven't really been focused on yet."

Bev Lessman, a Republican voter and small business owner from Sioux City, Iowa, is one of those voters still waiting to decide. She said she likes Scott, and attended an event he held in Le Mars, Iowa, in August. She's currently undecided, but is considering Scott, Haley, DeSantis and Trump. To her, electability is a crucial factor when considering who to support. But all things being equal, if she had to vote today, she would want to see Scott on the GOP ticket -- just not on the top line.

"I would actually vote for Nikki Haley and Tim Scott would be a great vice president," she said.

Honing in on rivals

When he first launched his campaign in May, Scott was viewed by many Republicans as one of a handful of White House hopefuls who could offer a viable threat to Trump in the primary. His personal narrative -- a Black man who grew up in poverty, was raised by a single mother in South Carolina and has since risen to the US Senate -- made him appealing to a wide group of voters, and his substantial war chest and connections to donors gave him stature in a crowded field.

But in the intervening months, other candidates, like fellow South Carolinian Haley, have gained some ground, while Scott has yet to have his moment. And as the primary calendar inches closer, some Republicans are anxiously hoping some candidates will fade away and allow support to build around the strongest alternative to Trump, who received 59% in the Fox poll of Republican primary voters releases earlier this month. At the moment, it's unclear if Scott can be that candidate.

"I think if Donald Trump wasn't in this race, it would be a very different discussion. But Trump casts such a large shadow over the rest of the Republican field, that it has stifled an ability for people to get traction," South Carolina conservative political strategist Dave Wilson told CNN.

"I think the only place where I really see traction taking hold, ironically, is with Nikki Haley. Her numbers continue to tick up and up and up," he added.

Haley's ascent has increased the pressure on Scott to either prove he can take on the former president or step aside to make room for other candidates. Last week, Washington Post columnist George Will called on Scott to drop out of the race and support Haley, an awkward proposal given that Will's wife, Mari, is an adviser to Scott's campaign. The opinion piece came on the heels of former Texas Rep. Will Hurd dropping out of the race and backing Haley earlier this month.

When asked by CNN about Will's piece after an event last week, Scott laughed off the call to drop out, joking "I guess this just proves there are mixed marriages," and said he plans to stay in the race.

Still, Scott has adopted a sharper, more aggressive rhetorical style in recent weeks and has shown a new willingness to attack rivals like Haley and DeSantis directly. Scott has used the aftermath of the Hamas terrorist attacks on Israel to harshly condemn President Joe Biden, who he said has "blood on his hands" following the attacks, as well as his Republican rivals. During a recent speech in Washington, DC, focused on Israel, he hit DeSantis and tech entrepreneur Vivek Ramaswamy for their "weakness and confusion" on foreign policy issues. And at a foreign policy panel at Georgetown University on Monday, Scott criticized Haley for saying not all Palestinians are antisemitic, part of an argument against accepting refugees from Gaza into the US. He falsely suggested Haley supports accepting refugees, insinuating she held the position "to be popular."

"How do we make sure that our nation remains the greatest nation on God's green earth if we have no ability to discern who's coming our country? I can't figure that out. If I can't figure that out, as commander in chief, I have a responsibility to take a leap back and say, not on my watch," Scott said. "Our nation is just too important for me to make bad decisions under pressure because I want to be popular. That doesn't work for me."

For Scott, harsh attacks on rival candidates can at times bristle against his typically optimistic campaign message. Yet he says efforts to distinguish himself from other candidates are focused on policy differences in part to preserve the Republican nominee's chances to defeat Biden in the general election, whomever that may be.

"My quest has always been to be an optimist, to be positive. I'm positive that showing the contrast between me and my opponents is a good thing, not a bad thing," Scott quipped in an interview with the "Ruthless" podcast released Thursday. "To the extent that we focus on those contrasts, I'm not going to make it personal."

"I don't want to poison the well so much so that everything that I say is going to be on a Democrat campaign ad," he added.