(Bloomberg) -- A super political action committee with close ties to billionaire donor Charles Koch is throwing its support behind Nikki Haley, saying she is the best candidate to thwart GOP frontrunner Donald Trump for the nomination.

Americans for Prosperity Action announced their plans in a memo Tuesday, saying Haley “offers America the opportunity to turn the page on the current political era, to win the Republican primary and defeat Joe Biden next November.”

“Our internal polling confirms what our activists are hearing and seeing from voters in the early primary states: Nikki Haley is in the best position to defeat Donald Trump in the primaries,” the memo said.

The group cited its grassroots organizing prowess and its data, which are likely to give Haley a strong boost in Iowa, where voters will caucus in less than two months. The group also said they would launch a multimillion dollar ad campaign this week in all early voting states and several Super Tuesday states.

The support comes at a critical time for Haley’s campaign. The former South Carolina governor is seeking to supplant Florida Governor Ron DeSantis as the top challenger to Trump in the GOP race. 

Haley has seen her campaign surge in the polls following strong debate performances that have sparked new interest from top Republican donors. Haley is now in third place behind Trump and DeSantis in the RealClearPolitics average of national polls. In Iowa, the polling average finds her trailing second-place DeSantis by just 3 percentage points.

“AFP Action’s members know that there is too much at stake in this election to sit on the sidelines,” Haley said in a statement, adding that she was grateful for the endorsement. 

Earlier: Nikki Haley Poaches Donors From Republican Rivals to Fuel Surge

The endorsement signals Koch is making his first foray into presidential politics since 2012, when Americans for Prosperity, a related political nonprofit that doesn’t disclose its donors, spent $33.5 million opposing President Barack Obama’s reelection. 

Americans for Prosperity spent $13.3 million opposing Democratic Senate candidates in 2016. Its allied super PAC, which became the main vehicle for directly influencing elections after it was set up in July 2018, spent $47 million on congressional races in 2020 but nothing to aid Trump’s reelection bid.

The move also speaks to the broader agita coursing through a swath of the donor class, which had looked toward the 2024 presidential election as a way to turn the page from Trump.

“This reflects the fact that Nikki has the wind at her back, donors believe she can win, and that Trump’s aura of invincibility is evaporating,” said Eric Levine, a New York lawyer and Republican fundraiser, said of the endorsement. Levine, who is co-hosting an event for Haley next week, said there is real enthusiasm among contributors for her campaign.

Despite staying out of the 2016 and 2020 presidential cycles, the group has the financial heft to try and boost Haley’s presidential bid. A June filing shows the group raised more than $70 million, with $25 million coming from Charles Koch himself.

“When we announced our decision to engage in our first-ever Republican presidential primary, we made it clear that we’d be looking for a candidate who can turn the page on our political dysfunction – and win. It’s clear that candidate is Nikki Haley,” Emily Seidel, senior advisor to AFP Action, said in a statement Tuesday.

Americans for Prosperity Action has vehemently opposed a Trump nomination and run ads saying that would lead to Biden’s reelection. In a February memo, the group announced plans to oppose Trump, urging voters to “turn the page on the past” and “write a new chapter” for the country.

Earlier: Charles Koch-Tied Group Seeks to Block Trump From GOP Nomination

Still it is unclear whether the endorsement from the Koch-backed network will be enough to help Haley overtake Trump. The president still holds a commanding lead in the GOP primary of nearly 48 percentage points over DeSantis, according to RealClearPolitics. 

Trump is looking to deliver a knock-out blow in Iowa, while DeSantis is pouring more resources into the state in the hopes that a strong showing can prolong his campaign.

--With assistance from Tom Maloney.

(Updates with additional details, background from fourth paragraph)

©2023 Bloomberg L.P.