FILE - Incumbent Florida Republican Gov. Ron DeSantis, his wife Casey and their children on stage after speaking to supporters at an election night party after winning his race for reelection in Tampa, Fla., Nov. 8, 2022. AP
DeSantis was considered a rising Republican star, but has been caught flat-footed by months of relentless attacks from the former president, who has surged into a commanding lead despite being engulfed in a firestorm of criminal investigations.
The 44-year-old governor will make his announcement in a livestreamed chat with billionaire Twitter owner Elon Musk on the network's audio platform as he bids to co-opt some of the tech mogul's star power to upstage Trump.
"I'm endorsing governor DeSantis -- he doesn't hold back and he's trying to make changes," one backer said in a video compilation of messages of support posted on Twitter by the Never Back Down political organization.
Musk teased the 6:00 pm (2200 GMT) Twitter Spaces event in remarks to a conference hosted by the Wall Street Journal, promising it would be live and unscripted, with "real time questions and answers."
The announcement will come with a campaign launch video and the start of a three-day retreat in Miami for some of DeSantis's wealthiest donors, who will be briefed on the campaign before the governor hits several early voting states next week.
Long viewed as the most viable challenger to twice-impeached Trump, DeSantis is better known than most of the hopefuls in the chasing pack for the Republican nomination -- but still lacks the frontrunner's national profile.
The launch format offers him a dual advantage -- giving him precious access to Musk's 140 million followers, many of whom are in Trump's base, and, if he wins the nomination, the attention of a chunk of younger, less conservative voters he will likely need for a shot at the White House.
DeSantis has used his platform as Florida's chief executive to burnish his conservative credentials, signing off on some 80 new state laws this spring, many targeting "woke indoctrination" in schools and other public institutions.
They include a ban on the discussion of gender identity and sexual orientation in schools, a block on funding for efforts to promote diversity at public universities and one of the most restrictive abortion laws in the country.
Never Back Down, which has been acting as the governor's de facto campaign arm, has a ground operation in most of the early nominating states and is making plans to expand.
But the launch comes with DeSantis's ratings in decline as a number of policy missteps have prompted disquiet about his readiness to take on Trump.
He faces the daunting task of closing an enormous polling gap, with Trump posting leads of close to 40 percentage points, despite being indicted on felony financial charges and being found liable for sexual abuse in a New York civil trial.
Jockeying for endorsements
Behind the scenes, the Trump and DeSantis camps have been jostling to secure political endorsements from state lawmakers while, at the national level, Florida's congressional delegation has broken heavily for Trump.
Musk is a well-known DeSantis admirer, although he was clear that Twitter would remain neutral on the nomination and that his hosting of the campaign launch should not be taken as an endorsement.
"I've said publicly that my preference, and I think the preference of most Americans, is... to have someone fairly normal in office," he said, without making any explicit criticism of Trump.
The former reality TV star was banned from Twitter after the 2021 assault on the US Capitol by his supporters and has not posted since being reinstated in November.
He has been attacking DeSantis almost daily on his record, character and fitness for office, but responded to Wednesday's announcement with relative restraint -- simply posting favorable polling on his own online platform, Truth Social.
"Announcing on Twitter is perfect for Ron DeSantis. This way he doesn't have to interact with people and the media can't ask him any questions," a Trump aide said.