Christie, who also ran for president in 2016, began his bid under the slogan “Because the truth matters” with a town hall in New Hampshire, which holds the nation’s first Republican primary following Iowa’s leadoff caucuses. After losing the nomination to Trump seven years ago, the former governor and federal prosecutor went on to become a close off-and-on adviser before breaking with the former president over his refusal to accept the results of the 2020 election.“Donald Trump made us smaller by dividing us even further and pitting us one against the other,” Christie said, suggesting that the former president was part of a broader political effort to “paint all Republicans with just one brush.”

He added that President Joe Biden “is doing the same thing, just on the other side.”

Christie enters a growing primary field that already includes Trump, Florida Gov. Ron DeSantis, former United Nations Ambassador Nikki Haley and U.S. Sen. Tim Scott of South Carolina. Former Vice President Mike Pence will be formally launching his own campaign in Iowa on Wednesday.

During his time as governor, Christie established a reputation as a fighter with a knack for creating viral moments of confrontation. But he faces an uphill battle to the nomination in a party that remains closely aligned with the former president, despite Trump’s reelection loss in 2020 and Republicans’ poorer-than-expected showing in the 2022 midterm elections.

Christie has become a fierce Trump critic in recent years and is now casting himself as the only Republican presidential candidate willing to openly pick fights with the former president — while also warning that the party failing to fully confront him will spark a repeat of the 2016 GOP primary, when Trump rolled over a host of alternatives with more political experience who split the support of voters opposing him.

Anti-Trump Republicans are particularly eager to see Christie spar with Trump on a debate stage — if, of course, Trump agrees to participate in primary debates and Christie meets the stringent fundraising criteria set by the Republican National Committee for participation.

JP Marzullo, a former state representative and former vice chairman of the New Hampshire Republican Party, previously backed Trump but is now supporting Christie.

“I think he’ll actually unite some of the voters, and he’ll get to independents,” Marzullo said of the former governor, adding, “I think it’s time for a change.”

Christie’s campaign will test the appetite among Republican voters for someone who has expressed support for many of Trump’s policies but has criticized the former president’s conduct. The former governor has rejected Trump’s lies that the 2020 election was stolen and has urged the party to move on or risk future losses.

Other Republicans with similar views, including former Maryland Gov. Larry Hogan and New Hampshire Gov. Chris Sununu, have opted against their own campaigns, expressing concerns that having more candidates in the race will only benefit Trump.