“Birdbrain. I call her birdbrain.” Donald Trump’s words form the cold open of a new campaign ad from Joe Biden’s US presidential re-election team. “If you voted for Nikki Haley,” the video continues, “Donald Trump doesn’t want your vote.” The 30-second ad, entitled Save America. Join Us, targets Haley voters in predominantly suburban battleground state postal districts where she performed well against Trump in Republican primary contests. It raises the prospect that the former president’s past disdain for Haley and her supporters could come back to haunt him if he fails to unite the party in November. It also signals how Biden, a longtime champion of bipartisanship, is seeking to reach across the aisle one last time, courting moderate Republicans who cannot stomach their own party’s nominee. In a tightly contested election likely to be won in the margins, this constituency could make all the difference. Tara Setmayer, a former Republican communications director on Capitol Hill, said: “It’s incredibly smart of the Biden campaign to begin planting the seeds to give Haley voters and swing state independent voters a permission structure to vote for him. “Partisanship and loyalty to your tribe has become a very powerful tool and breaking away from that has been incredibly difficult for a lot of people. But Donald Trump’s antics, rantings, continued extremism and attacks on women in particular are making it very difficult for those Haley voters to stay under the tent with Trump.” The Biden campaign sees an opening in continued Republican opposition to Trump even after he clinched the party nomination last month. Haley dropped out of the primary race after Super Tuesday on 5 March but pointedly did not endorse the former president. Since then an average 17% of voters in Republican contests have registered what are in effect protest votes in favor of Haley, Ron DeSantis or other defunct candidates. In the crucial battleground state of Wisconsin this week, about 13% of Republicans voted for Haley. Donald Trump’s antics ... are making it very difficult for those Haley voters to stay under the tent with Trump Tara Setmayer There is little sign of Trump seeking to win these dissenters back. He has reportedly not called Haley since her withdrawal from the race. Steve Bannon, a former Trump ally, said on his podcast after Super Tuesday: “Screw Nikki Haley – we don’t need her endorsement.” Trump has used incendiary language and pushed an extreme agenda instead of making the nominee’s traditional pivot towards the political centre. Elaine Kamarck, a senior fellow at the Brookings Institution thinktank in Washington, said: “Trump has continued to get crazier and crazier. If he had been running a more normal campaign where he reached out to Haley voters, where he reached out to disaffected Democrats, it’s one thing, but instead he’s running a campaign that’s based on hatred and retribution and he’s more incoherent than ever.” Biden, by contrast, has offered a message of inclusiveness. He said in a statement last month: “Donald Trump made it clear he doesn’t want Nikki Haley’s supporters. I want to be clear: there is a place for them in my campaign.” Haley’s donors, whom in January Trump threatened to blacklist, are another target for the Biden campaign. The CNBC network reported that at least half a dozen former Haley bundlers – people who organise and collect campaign contributions from other donors – have chosen to help Biden rather than Trump. It noted the creation of a WhatsApp group named “Haley Supporters for Biden”. Some Haley voters and other moderate Republicans are likely to fall into line in November when faced with a binary choice between Trump and his Democratic rival. But others, perhaps considering the 45th president an existential threat to American democracy, might back Biden or not vote at all. Joe Biden’s not a concept any more, as he was in 2020; he’s now a reality Bill Whalen That decision could rest not only on their antipathy towards Trump but how palatable they find Biden’s first term as president. On the upside, he has pulled off a series of bipartisan legislative achievements on infrastructure, computer chip manufacturing and gun safety. His foreign policy is also more in step with Ronald Reagan Republicans than the isolationist “America first” creed of Trump. Setmayer, a senior adviser to the Lincoln Project, an anti-Trump group, said: “He’s not an apologist for Putin and authoritarians. That appeals to the foreign policy hawks in the Republican party who are uncomfortable with Trump’s attacks on Ukraine and not supporting Nato.” But Biden’s appeal to moderate Republicans could face a rougher ride than it did in 2020, when many were seeking relief from Trump’s chaotic presidency and mishandling of the coronavirus pandemic. The president’s bold spending, investing trillions of dollars in Covid relief and the climate crisis, is anathema to many conservatives, who also condemn his military withdrawal from Afghanistan and handling of illegal immigration. Bill Whalen, who was an aide to the former Republican governors of California Pete Wilson and Arnold Schwarzenegger, said: “This is a key problem with Joe Biden’s re-election. Joe Biden’s not a concept any more, as he was in 2020 - he’s now a reality. We’re not dealing with hypotheticals: how would he run this presidency, will he be bipartisan, will he be moderate, will he be more of an old school Democrat? “No, he’s proven not to be those. So to try to go back and recreate 2020, gosh, nobody wants a pandemic but he just cannot bring that Joe Biden back.” At the 2020 Democratic national convention the former Ohio governor John Kasich, the ex-New Jersey governor Christine Todd Whitman, the former New York congresswoman Susan Molinari and Meg Whitman, a former candidate for governor of California, crossed the partisan divide to urge fellow Republicans to support Biden’s candidacy. But this time, some of Trump’s harshest critics remain reluctant to throw their weight behind the current president. In January Liz Cheney, a former Republican congresswoman, declined to commit to voting for Biden. Last week Mark Esper, a former Trump defense secretary, said he would definitely not vote for his old boss but, when pressed on whether he would support Biden, admitted: “I’m not there yet.” We have our grassroots supporters – everyday relatable voters willing to stick their neck out and say, ‘I previously supported Trump but I can’t’ Gunner Ramer Henry Olsen, a senior fellow at the Ethics and Public Policy Center thinktank in Washington, said: “In 2020 he was not an unknown quantity but one could believe that he would be more bipartisan, more open to Republicans than he’s ended up being, and so consequently disappointed Republicans were willing take a chance on Biden. Clearly some of those people will still be with him but he would be doing much better if most of them were still with him. “He does have a record to run on now. It’s a record that Republicans in particular are going to be unhappy with. There’s pretty much no area where Biden has done things that matter successfully that appeal to Republican priorities, which is another reason why the border is so important. Even more moderate Republicans think that’s very important but he doesn’t seem to be able or willing to accommodate their priorities.” Voters turned off by both Biden and Trump have been dubbed “double haters”. The election may come down to which candidate they hate a little less. Gunner Ramer, political director of Republican Voters Against Trump, said: “When Trump is in general election mode and he is brought front and centre to these swing voters, we anticipate Biden’s poll numbers strengthening. What does it mean for our country, for our democratic allies, for our democracy if Trump is once again president? It scares voters.” Republican Voters Against Trump this week released an ad featuring a former Trump voter explaining why he cannot support him again. Ramer urged former Trump officials and military generals to do more than merely express their misgivings to journalists or authors. “I encourage them to be more honest and more forthright with how serious of a threat Trump is to our democracy because they were closest to it,” he said. “That’s why I think Mike Pence refusing to endorse Donald Trump was important. But there are so many more out there who could speak up. “It’s frustrating because we have our grassroots supporters – everyday relatable voters willing to stick their neck out and say, ‘I previously supported Trump but I can’t.’ It shows tremendous courage and bravery but there are people who know better who could do a lot more to stand up against Donald Trump.”