The political network founded by the Koch brothers is endorsing Nikki Haley in the Republican presidential primary race, giving her organizational muscle and financial heft as she battles Gov. Ron DeSantis of Florida for second place in Iowa.
The group announced its plans in a memo on Tuesday.
The commitment by the network, Americans for Prosperity Action, bolsters Ms. Haley as the campaign enters the final seven weeks before the first nominating contest. Since the first Republican primary debate, Ms. Haley has steadily climbed in polls, and is closely competing with Mr. DeSantis for the second-place slot in Iowa. Former President Donald J. Trump remains the dominant front-runner in the race.
Ms. Haley, who has described Mr. Trump’s time as past, has gained support from donors and her candidacy has received approval from elite opinion-makers, many of whom describe her as the best alternative to Mr. Trump.
But Ms. Haley’s campaign does not have the organizational strength that Mr. DeSantis does, thanks to work the super PAC affiliated with his campaign has been doing for much of the year.
The endorsement from the super PAC established by David and Charles Koch could help change that. It will give her access to a direct-mail operation, field workers to knock on doors and people making phone calls to prospective voters in Iowa and beyond. The group also has money to spend on television advertisements.
It also helps fuel Ms. Haley’s momentum heading into the final weeks before voting begins.
Americans for Prosperity Action has been among the country’s largest spenders on anti-Trump material this year, buying online ads and sending mailers to voters in a number of states, including Iowa, New Hampshire and South Carolina. All told, the group has spent more than $9 million in independent expenditures opposing Mr. Trump.
One mailer in Iowa, paid for by AFP Action, shows images of Mr. Trump and Mr. Biden and reads, “You can stop Biden…by letting go of Trump.”
But so far none of that spending has benefited any of his rivals, who have been busily battling each other.
The Koch network is well financed, raising more than $70 million for political races as of this summer.
The group has been committed to opposing Mr. Trump’s return as leader of the Republican Party. In a February 2023 memo, Emily Seidel, the president of Americans for Prosperity, wrote, “We need to turn the page on the past. So the best thing for the country would be to have a president in 2025 who represents a new chapter.”
Mr. DeSantis’s campaign, which has seen upheaval in recent days including the C.E.O. of his super PAC resigning, tried to throw cold water on the endorsement before it was even announced.
“Every dollar spent on Nikki Haley’s candidacy should be reported as an in-kind to the Trump campaign,” wrote a DeSantis spokesman, Andrew Romeo, on X, the website formerly known as Twitter, thirty minutes before A.F.P. Action officials announced the endorsement in a press call.
“No one has a stronger record of beating the establishment than Ron DeSantis, and this time will be no different,” he wrote.
