Former US President Donald Trump spent the three-year anniversary of his White House departure trying to sweep away the few remaining Republican obstacles to his third consecutive nomination, hammering former South Carolina Gov. Nikki Haley and warning supporters against complacency two days ahead of the New Hampshire primary. "We need big margins," Trump said at a rally in Manchester, "because we have to send real unity as a message." But over more than 90 minutes, Trump delivered the vengeful message that he has made the focus of his campaign, moaning about the lost 2020 race; defending the Jan. 6, 2021, rioters; pushing again for the Supreme Court to declare him and all presidents immune from prosecution; mocking President Joe Biden; and, with the most gusto, lashing out at Haley, his former UN ambassador and the candidate closest to him in Granite State primary polls. Even before he spoke, Trump's campaign beamed its message on a big screen above the stage with rotating slides attacking Haley over supposed ties to "Democrats, Wall Street & Globalists" and her positions on Social Security and other hot-button issues. When he took the microphone, Trump kept up the barrage. "Nikki Haley is using radical Democrat money to run the radical Democratic campaign operation she's running," Trump said, referencing his rival's appeal to some centrist and anti-Trump political groups and donors. "What the hell kind of Republican candidate is that?" After running through a laundry list of policy criticisms, most pointedly Haley's campaign pledge to raise the retirement age for younger people, delaying their access to Social Security payments, Trump jabbed back at Haley over her suggestion that he is too old to be president again — which followed an incident in which Trump confused her with former House Speaker Nancy Pelosi. "The concern I have is — I'm not saying anything derogatory, but when you're dealing with the pressures of a presidency, we can't have someone else that we question whether they're mentally fit to do it," Haley, 52, said earlier Saturday of Trump, 77, at a rally in Keene, New Hampshire. Trump shot back at the rally, claiming he's recently taken a "cognitive test," which he "aced," before promising to "let you know when I go bad." After finishing third in Iowa behind Florida Gov. Ron DeSantis, Haley's campaign is on the line in New Hampshire. According to recent polling, she is the only GOP candidate within walking distance of Trump in the state, which has a less conservative profile than Iowa and allows independents to vote in party primaries. Granite State voting rules — and their potential to help Haley — were a frequent target for Trump on Saturday night, as the former president groused over the potential for those who don't consider themselves Republicans or typically vote for the GOP to cast ballots in its presidential primary. But he added a false flourish to that case, telling the audience that Democrats, too, can take part on the Republican contest. They cannot. "Registered Democrats cannot vote in the Republican primary, and registered Republicans cannot vote in the Democratic primary," New Hampshire Secretary of State David Scanlan told CNN earlier this week after Trump leveled a similar charge. Trump also looked ahead to the next major clash in the race: South Carolina. It's Haley's home state, where she was twice elected governor, but Trump leads there in the polls and among influential GOP leaders — a handful of whom showed up in New Hampshire. "We could be in our home state, but we chose to come up to New Hampshire for a reason," Rep. Russell Fry said. Gov. Henry McMaster invoked the Spice Girls — really — to tell voters "what we want, what we really really want" is Trump. Again, it was Trump's desires that took centerstage. He repeated his contention that all US presidents, beginning with him, should have immunity from prosecution. This relatively new line of argument comes as Trump awaits a ruling from a federal appeals court regarding his attempts to overturn the 2020 election. In the meantime, he's argued presidents should never face legal consequences for their actions. The court hearing the claim has expressed skepticism, but Trump is continuing to make his case in public. On Saturday night, he invoked President Harry Truman's use of the nuclear bomb in Japan in 1945 as a case study. "Look at Harry Truman," Trump said. "He wouldn't have done, if you think Hiroshima, not exactly a nice act but it did end the Second World War probably, right? Nagasaki. He wouldn't be doing that; he said, 'I don't want to do that because my opponents will indict me.'" The US dropped atomic bombs on both cities toward the end of the war, killing at least 150,000 in Hiroshima alone, according to some estimates. Though the morality of the decision has been debated, no one sought to bring legal charges against Truman. Trump had much less to say about DeSantis. He even made a point of noting how little he'd spoken about the Florida governor (before proceeding to mock his height at the prompting of a supporter). He had more kind words, though, for Hungary's right-wing prime minister, Viktor Orban. "It's nice to have a strong man running your country," Trump said of the strongman, happily reciting the nice things that Orban has recently said about him. — CNN