The former New Jersey governor Chris Christie has confirmed his candidacy for the Republican presidential nomination next year. Christie filed paperwork with the Federal Election Commission on Tuesday afternoon. He was scheduled to announce his presidential run hours later in a town hall hosted at the New Hampshire Institute of Politics in Manchester, New Hampshire. The pugilistic politician joins the primary as a rank outsider but promises a campaign with a singular focus: to take the fight to Donald Trump, the former president who left office in disgrace after the January 6 attack on Congress but who is the clear frontrunner to face Joe Biden again at the polls. Such is Trump’s dominance of Republican polling – in which he leads his closest challenger, Florida governor Ron DeSantis, by wide margins – others in the field have been slow to turn their fire Trump’s way. Declared but low-polling candidates include the former South Carolina governor Nikki Haley, the South Carolina senator Tim Scott, the former Arkansas governor Asa Hutchinson and Vivek Ramaswamy, a biotech entrepreneur. While Christie has insisted he is “not a paid assassin”, the 60-year-old is certainly a seasoned brawler. Christie’s claims to fame include leaving office in New Jersey amid a scandal about political payback involving traffic on the George Washington Bridge to New York, then leaving the Florida senator Marco Rubio’s 2016 presidential campaign in pieces after a debate-stage clash for the ages. Christie was quick to drop out of that campaign, then equally quick to endorse the clear frontrunner. He stayed loyal despite a brutal firing as Trump’s transition coordinator, fueled by old enmities with Trump’s son-in-law, Jared Kushner, and only broke from Trump after the Capitol attack. Recently, Christie has worked for ABC News as a political analyst, honing his turn of phrase. Speaking to Politico, he insisted he was serious about winning the primary. “I’m not a paid assassin,” he said. “When you’re waking up for your 45th morning at the Hilton Garden Inn in Manchester [New Hampshire], you better think you can win, because that walk from the bed to the shower, if you don’t think you can win, it’s hard.” He also said Trump “needs to be called out and … needs to be called out by somebody who knows him. Nobody knows Donald Trump better than I do.” Trump has taken practice swings of his own. “I hear Chris Christie’s coming in,” Trump told Fox News at an Iowa town hall. “He was at 6% in New Jersey … I love New Jersey, but 6% approval rating in New Jersey. What’s the purpose? And he’s polling at zero.” Most observers think Christie’s second presidential campaign will struggle to last even as long as his first. But not all think he will drop out without leaving his mark. In the Washington Post, columnist Jennifer Rubin said Christie, having followed Trump then abandoned him, “can help create a rationale (what psychologists call a ‘permission structure’) that allows Republicans who voted for Trump to move on”. Rubin also said Christie could be a “truth-teller who can force Republicans to confront reality … and, as a bonus, Christie might be just the right person to take down the other bully in the race: DeSantis.”