Nikki Haley, who once served as U.N. Ambassador and South Carolina governor, received a major endorsement from one of the biggest conservative activist groups in the country, Americans for Prosperity (AFP), on Tuesday. The endorsement adds another layer of complexity to the current Republican presidential primary.

Haley, who has been picking up some momentum in the polling, is seen as one of the three top contenders in the primary. She is vying with Florida Governor Ron DeSantis for second place behind former president Donald Trump, who still has a commanding lead on both of them.

AFP's endorsement is a wrinkle in the race for both Trump and DeSantis, who are both looking for stronger fundraising in a primary that is using up a lot of Republican resources. The organization, however, says it is time to offer "America the opportunity to turn the page on the current political era."

AFP Action stayed out of the 2016 and 2020 presidential cycles but has significant resources to try and boost Haley's campaign: The group reported raising more than $70 million in its last public filing, in June, with $25 million coming from Koch himself and another $25 million from one of his nonprofit groups.

The group first announced plans to oppose Trump back in February, based in large part on concerns about his ability to defeat President Joe Biden. Since then, however, the Republican base has only embraced Trump more.

He now leads his closest primary rival in national polls, Florida Gov. Ron DeSantis, by nearly 50 points in 538's average. Haley narrowly trails DeSantis in the national average.

But the situation in early-voting states is slightly different and Trump is a relatively weaker front-runner there, even though he still leads the field by double digits.

AFP is also working on an ad campaign for Haley using those resources.

Haley and DeSantis have been attacking each other in recent weeks - and most notably during a recent primary debate - as the two hope to prove to voters they are a better alternative to Trump. Haley, in particular, is hoping to use her experience as a former Ambassador to the United Nations to solidify support from the more neoconservative wing of the party, as well as offer what her campaign seems to be messaging as a more level-headed approach to domestic policy.

Haley says that she's "honored" to have gotten the support of AFP.

"I’m honored to have the support of @AFPAction, including its millions of grassroots members all across the country," she said in a statement and in a tweet on Tuesday morning. "This election is a choice between freedom & socialism, individual liberty & big government, fiscal responsibility & spiraling debt. We have a country to save."

The latest poll, from Emerson College, has Haley ahead of DeSantis, with 9 percent of the vote to DeSantis' 8 percent. Trump is far ahead of both with 55 percent. In Iowa, recent polling has Haley behind DeSantis.