Trump backer-turned-critic Chris Christie makes White House run official

Former New Jersey Governor Chris Christie on Tuesday formally launched his 2024 presidential campaign, joining a growing Republican field led by former President Donald Trump.

Christie, who served as an adviser to Trump's successful 2016 campaign but has since become a vocal critic over his false claims that the 2020 election was rigged, filed paperwork declaring his candidacy. He is scheduled to announce his White House bid later on Tuesday at Saint Anselm College in Manchester, New Hampshire.

A former federal prosecutor, Christie, 60, has argued he is the only potential rival with the skills and willingness to attack Trump directly.

Christie has not fared well in public opinion polling thus far, however. He netted just 1% support from potential Republican primary voters in a Reuters/Ipsos poll in May, compared to Trump's 49% support and Florida Governor Ron DeSantis' 19% support.

Other Republicans seeking to challenge President Joe Biden include former UN Ambassador Nikki Haley and US Senator Tim Scott. Former Vice President Mike Pence is set to enter the race on Wednesday.

Christie's former runs for president

Christie ran for president in 2016 but ended his bid after a disappointing finish in the New Hampshire primary and became the first major party figure to throw his support behind Trump.

He since has urged Republicans to disavow Trump's assertions about the 2020 election and told reporters he would not vote for Trump in 2024, even if Trump won the nomination.

That strategy may entice Republican voters who are ready to move past Trump, but it remains unclear whether any Republican can prevail without the support of Trump's still-loyal base.

As an underdog, Christie could end up playing the role of spoiler, a position he found himself occupying in 2016, when his dissection of US Senator Marco Rubio at a debate days before Christie dropped out of the race blunted Rubio's momentum.

Christie first emerged as a national figure on the strength of his two terms from 2009 to 2017 as governor of Democratic-leaning New Jersey, where his confrontational approach to politics earned him plaudits from admirers and accusations of bullying from detractors.

His tenure was tarnished by the so-called "Bridgegate" scandal, in which two allies deliberately shut down lanes at the heavily trafficked George Washington Bridge between New Jersey and New York City to punish a local mayor for failing to endorse Christie's re-election.

Christie has said he was unaware of the plot at the time, but witnesses at a criminal trial for the two allies testified that the governor knew about the lane closures.

Despite his early support for Trump, Christie was passed over for vice president and for attorney general, and was fired as the head of Trump's transition team just three days after the 2016 election.