Donald Trump’s voters get all the attention. But it’s Joe Biden’s who may decide the general election. A historic rematch for the White House between the ex-president and the current president — which few Americans seem to relish — is coming into view given Trump’s early dominance of the Republican primary process. Ever since Trump burst into national politics in 2015, academics, journalists and political professionals have devoted extraordinary efforts to understanding the economic, ideological, emotional and patriotic motivations of his ultra-loyal “Make America Great Again” followers. But there is a strong case that it will be the more diverse groups of voters who chose Biden in 2020 who hold the key to November’s election, depending on their level of enthusiasm and shifting political priorities. Democratic political operatives admit Biden faces a tough mission. The former president’s supporters are enthusiastic and up for the fight, and he’s sporting a far more formidable political operation than he did in either 2016 or 2020, which he will use to try to expand his pool of tens of millions of Republican voters. Local Republican officials are predicting that Biden’s hopes will be complicated by the return of many Republicans who were repulsed by the ex-president’s conduct in 2020, but who now view his presidency more warmly and have been repelled by what they see as the current president’s march to the left. Trump’s ascent — which is remarkable given his quagmire of legal threats and his assault on democracy in 2021 — is coinciding with rising concern among Democrats about the durability of the support base that carried Biden to the White House three years ago. This time, Biden faces the complications of incumbency, when he will be judged on his own record – unlike in 2020 when he exploited the chaotic pandemic leadership of a president who mused on camera whether injecting disinfectant could cure Covid-19. If Trump represents an existential threat to free US elections, as his critics charge, Biden needs to muster voters, comprising all of the elements of the traditional Democratic coalition and beyond to defeat him again. Signs that an unpopular president’s broad support base is fraying or disengaged have caused alarm among his supporters – and are offering encouragement to Trump. Twice in the last two days, Biden has been interrupted at public events by protesters demanding a ceasefire in Gaza, who have, literally, impeded his attempt to get his general election message out. Their anger crystalized the alienation of some progressive, young and Arab American voters — all important elements of Biden’s bid to win reelection in swing states — with his support for Israel’s response to Hamas terror attacks. A decision by such voters that they cannot morally support Biden over this single issue could have a significant impact. Quentin Fulks, Biden’s principal deputy campaign manager, said hours after Trump’s victory in the New Hampshire primary on Tuesday that the president had a far broader, and more powerful, base than his potential opponent. “We should … not forget how President Biden beat Trump in 2020. By assembling a diverse coalition including voters of color, young voters, suburban voters, including suburban women, and making gains among rural and white working class voters in battleground states,” Fulks said. “The GOP primary has laid bare the stark and indisputable reality that while Donald Trump has the united support of his MAGA base, he is struggling to make himself palatable to these key constituencies that will ultimately decide the election this November.” The complexities of incumbency The backlash to Biden’s handling of Israel epitomizes one of the complications of power. Every step a president takes at home and abroad can cause a detrimental counter reaction. Successful presidents constantly have to balance and mitigate the effect of actions they take in the national interest or to advance their own sometimes conflicting positions. One example is Biden’s attempt to wipe out tens of billions of dollars in student loan debt, which have been sometimes frustrated by the courts. Such steps are popular with younger, progressive and minority voters saddled with federal loans. But Republicans, seeking to make inroads in traditional Democratic blue collar constituencies, brand such programs as a giveaway that discriminates against working Americans who didn’t go to college. Biden faces another balancing act on the environment. Failing to take bold steps to tackle climate change would risk demoralizing progressive and younger voters. But Republican candidates are, for example, exploiting public skepticism about the use and range of electric vehicles in some key battlegrounds. The president faces another painful political choice as he seeks a deal with Republicans to defuse the crisis at the southern border. Accepting what liberals see as draconian Trump-style restrictions on asylum would be viewed as a betrayal by many in Biden’s coalition. But he badly needs to defuse a political liability on an issue that is increasingly critical in the looming general election and could hamper his reelection hopes. Democratic Rep. Pramila Jayapal, who heads the Congressional Progressive Caucus, warned before Christmas that doing a deal with Republicans on the issue could be politically disastrous for Biden. “We have to put together a coalition that is the same coalition we delivered in 2020, for him to win the White House for us to win the Senate and for us to take back the House,” Jayapal told CNN’s Manu Raju. “And that coalition involves a lot of young voters. It involves a lot of immigrant voters, it involves a lot of folks of color, and this issue of immigration is critically important to them.” Fears about the durability of Biden’s coalition have been spurred by his rock-bottom approval rating, which has hovered at or below 40% for months – in perilous territory for a president seeking reelection. The possibility that base could shatter was laid bare in polling last year that identified a weakness among the voters among whom he needs to demonstrate strength. A CNN survey in November, for example, showed Biden led Trump among Black voters 73% to 23%. But he won this cohort by 75 points in 2020. Latino voters favored Biden over Trump by only four points in the poll compared to 33 points in the 2020 election. The former president was winning independent voters by four points in the CNN poll but lost them to Biden by 13 points in 2020. The biggest danger for Biden may not be that these voters defect directly to Trump, but that they fail to vote at all, in a way that thins his critical margins. There is not much room for error. While he secured a comfortable 306 to 232 victory in the Electoral College over Trump, the win was a lot closer than it looked. In Wisconsin, for instance, Biden won by about 20,000 votes among more than 3 million cast. In Georgia, he prevailed by 11,700 votes, and in Arizona by just over 10,000 votes. Any fraying of Biden’s electoral edge, defections to Trump or no-shows in these states could land Trump back in the White House. Biden’s campaign has argued that once Americans are reminded of Trump’s aberrant behavior — less obvious during his political exile in Florida — they will flock back to Biden to prevent the ex-president from returning to power, even if they are not fully satisfied with the last three years. Such arguments may have been reinforced on Tuesday by Trump’s self-absorbed New Hampshire victory speech in which he vented about South Carolina Gov. Nikki Haley’s refusal to be bullied out of the GOP primary race. Some Democrats also point to a Biden legislative record that, despite disappointing some on the left, compares favorably with any Democratic president since Lyndon Johnson in the 1960s. “Coalitions are ever evolving and you have to stay on top of them and I think the president has,” said Hank Naughton, president of Centrist Democrats of America. Naughton argued that if Biden could communicate his successes – on the economy and foreign policy – and the lack of a positive agenda from Trump, who has promised to wage a second term dedicated to “retribution,” he could reassemble his base. “Yes, it’s going to be a hard slog, no doubt about that. But I think this coalition has grown and, in many ways, we can keep that together,” Naughton said, also predicting many independents and Republicans who disdain Trump won’t be able to “hold their nose” and vote for him and will either chose Biden or stay at home in November. As the prospect of a Trump vs. Biden general election have firmed up in recent weeks, the White House has accelerated its efforts to court key constituencies and shore up the president’s electoral standing. Vice President Kamala Harris has been sent to campaign where she is most effective, including as the key messenger to women voters as Democrats seek to exploit anger over the Supreme Court’s overturning of the federal constitutional right to an abortion. Harris is also seeking to mobilize voters of color in swing states like Georgia. Biden, meanwhile, is targeting blue collar areas where he’s long felt comfortable. On Wednesday, he accepted the endorsement of the United Auto Workers union. And while the powerful union’s backing doesn’t necessarily mean all auto workers will be with him, it was a victory over Trump, who sought to use a now-solved strike in the industry and Biden’s support for electric vehicles, to separate the president from a union constituency that is especially key in Michigan. “Joe Biden bet on the American worker while Donald Trump blamed the American workers,” UAW President Shawn Fain said. Trump seeks to weaken Biden’s coalition According to the Pew Research Center, both Biden and Trump expanded their respective party coalitions in 2020 with the current president doing a slightly better job. Biden did well with suburban voters especially and attracted the traditional Democratic coalition of Black, Hispanic and Asian and Pacific Islander Americans. He made gains with men, but Trump did make inroads among Hispanics and women. Both campaigns are aggressively seeking to solidify their 2020 advances while identifying swathes of first-time voters. This is an area where the ex-president’s newly professional political machine could become a significant factor in the 2024 election. Trump’s shrewd choice of issues – immigration, the economy, crime and foreign policy – is intended to play into and foment a sense among many voters that the country is tipping out of control and is vulnerable to outside threats. Despite strong economic indicators and the fact that a complex world is beyond the capacity of a US president to control, voters who are struggling or worried about security may not see it that way. Some Republicans – observing Trump’s strength in the early nominating contests and cognizant of Biden’s struggles – argue that Republicans who opposed Trump in 2020 will return to the Republican ticket in 2024 amid disillusionment with Biden’s liberal agenda. “They’re back,” said Chuck Morse, a veteran Republican officeholder in New Hampshire who is seeking the Republican nomination for governor. “I think the one thing that is happening not just here, but everywhere, people are disgusted with Washington. Obviously the border is playing a big role in that,” Morse, who has endorsed Trump, said in an interview. “People want that order and they think Trump can deliver that.” Dominick Lombardi, vice chairman of the Orange Republican Party in New Haven County, Connecticut, agreed, arguing that GOP voters he knows have seen the results of a Biden presidency and now favor Trump. “They didn’t like his act or his Twitter, but he got things done,” said Lombardi, who was wearing a red “Make America Great Again” baseball cap at a Trump rally in New Hampshire last weekend.