The re-election of Donald Trump would bring “four more years of chaos” the US “won’t survive”, the former president’s closest challenger for the Republican nomination, Nikki Haley, told an Iowa audience, turning her fire on the frontrunner as the first vote of the 2024 primary looms. The former South Carolina governor has caught up with Ron DeSantis, the hard-right governor of Florida, in the battle for second place in Republican presidential polling. The gap between Haley and Trump is also closing, particularly in New Hampshire, the second state to vote when it holds its primary on 23 January. Trump faces a slate of criminal and civil trials as well as attempts to keep him off the ballot, for inciting the 6 January 2021 insurrection. Nonetheless, he remains formidably popular with the Republican base and Haley, who as UN ambassador under Trump was often touted as a potential vice-president, must perform a balancing act on the campaign trail. In Iowa, she said Trump had been “the right president at the right time”. But she added: “The reality is, rightly or wrongly, chaos follows him, and we all know that’s true … and we can’t have a country in disarray and a world on fire and go through four more years of chaos. We won’t survive it.” Saying she used to tell Trump he was “his own worst enemy”, Haley added: “We have a country to save, and that means no more drama. No more taking things personally.” Haley was speaking in Des Moines, as CNN hosted town hall events for her and DeSantis, rivals who will also meet on the debate stage next week, as Trump continues to avoid such traditional forums. DeSantis also used his airtime to attack Trump, but Haley is widely seen to have acquired greater momentum and therefore attracted greater attention. A confident performer and stump speaker, she is not immune to gaffes. On stage at Grand View University, she addressed her controversial failure last week in New Hampshire to say slavery caused the civil war. Saying she “had Black friends growing up”, and that slavery was “a very talked-about thing” in her state (the first to secede in 1860, its declaration of secession citing slavery as the cause), Haley said: “I shouldn’t have done that. I should have said slavery. But in my mind that’s a given, that everybody associates the civil war with slavery.” She was also forced to deal with a remark in New Hampshire only the day before, when she appeared to dismiss the importance of Iowa, telling voters: “You know how to do this. You know Iowa starts it. You know that you correct it.” DeSantis is Trump’s closest challenger in Iowa, Haley closest in New Hampshire. In Iowa, Haley claimed she had been joking. “You are going to see me fight until the very end, on the last day in Iowa,” she said. “And I’m not playing in one state. I’m fighting in every state. Because I think everybody’s worth fighting for.” Trump’s campaign has switched to a fighting stance, airing its first attack ad against Haley in New Hampshire this week, portraying her as soft on immigration. That offensive coincided with Haley securing the endorsement of Don Bolduc, a far-right former special forces general who ran for US Senate with Trump’s backing but now says: “With Trump, there’s too many distractions. There’s too much risk of losing.” Still, any Trump opponent faces an uphill fight: Haley’s state, South Carolina, will vote in February and she trails Trump there by about 30 points. There are also other candidates still in the race. On Thursday, the former New Jersey governor Chris Christie, the only explicitly anti-Trump candidate, pinning his hopes on New Hampshire, angrily rejected calls to drop out and throw his weight behind Haley. “The fact is that I’m running for president of the United States and no one’s voted yet,” Christie told Hugh Hewitt, a rightwing radio host, in an interview that started awkwardly and went downhill from there. “And I don’t have an obligation to do anything other than to answer questions, tell the truth, run a good campaign, and try to win. And so, you know, where this has become Nikki Haley’s campaign when no one’s voted yet is kind of a mystery to me.” The biotech entrepreneur Vivek Ramaswamy and the former Arkansas governor Asa Hutchinson are also still in the race. But their odds are even longer than Christie’s. On Friday, writing on Substack, the Republican operative turned anti-Trump crusader Steve Schmidt said: “Nikki Haley is an imitation of Trump, a hollow woman … firmly on Trump’s side of the field. She is an acolyte who has strayed, probably much to Trump’s amusement because he knows she will be back in the menagerie more loyal than ever. “It is Chris Christie who stands alone against Trump. He is … the only moral choice.” Christie, however, told Hewitt that if he did not win the nomination, and even if Trump did, he would not vote for Joe Biden.