Several prominent Republican donors have chosen to back former President Donald Trump in the 2024 presidential election despite turning on him after the 2020 election and the Jan. 6, 2021, Capitol riot.

With just two months until the Iowa caucuses and the start of the 2024 election cycle, donors are losing faith in supporting any candidate besides Trump, who is the front-runner to be the GOP nominee and retains a major polling lead over his opponents.

“While Trump may have not been some Republicans’ first choice for 2024, many are coming back on board because the risk of Joe Biden being a two-term president is just too high,” Charlie Kolean, a GOP strategist who raises money for Trump, told ABC News. “His lead in the polls is unparalleled, and barring any legal action, there is nothing politically that could stop him from becoming the nominee.”

Oil mogul Harold Hamm and Home Depot co-founder Bernie Marcus are among the donors who withheld their support for the former president following the 2020 election and the Jan. 6 riot but have now endorsed Trump.

“I understand the frustration of some of my Republican friends who do not like or are offended by things Donald Trump does and says,” Marcus wrote in an op-ed for Real Clear Politics earlier this month. “I, too, have been frustrated at times, but we cannot let his brash style be the reason we walk away from his otherwise excellent stewardship of the United States during his first term in office.”

Marcus donated to former South Carolina Gov. Nikki Haley’s campaign in March. Hamm also donated to Haley’s and Gov. Ron DeSantis’s (R-FL) presidential campaigns earlier this year before donating $200,000 to a pro-Trump super PAC last month. The donation came after a private meeting between Trump and Hamm occurred at Trump’s Mar-a-Lago resort.

Some donors see challenges to Trump this year as a test for future elections. Republican donor Don Tapia, a U.S. ambassador to Jamaica in the Trump administration, said Haley has a good donor base and showed potential for 2028 but was not 2024 material.

“When I looked there [at the other candidates], it was only a training session for the people that’s on that platform right now,” Tapia told ABC News.

Haley and DeSantis are polling at least 20 points behind Trump for the Republican nomination, but Haley has seen the strongest numbers in a theoretical showdown against Biden.