Gov. Ron DeSantis of Florida escalated his hostilities with former President Donald J. Trump on Friday, arguing that his Republican presidential rival was weak on crime and immigration, and accusing him of ceding critical decision-making during the coronavirus pandemic to Dr. Anthony S. Fauci.
In an appearance with the conservative commentator Ben Shapiro, Mr. DeSantis accused Mr. Trump, the G.O.P. front-runner, of “moving left” on criminal justice and immigration issues after winning over the party’s base in 2015 and 2016.
He pledged that he would repeal what is known as the First Step Act, a bipartisan criminal justice measure signed into law by Mr. Trump in 2018 that expanded early-release programs and modified sentencing laws, including mandatory minimum sentences for nonviolent drug offenders.
“He enacted a bill, basically a jailbreak bill,” Mr. DeSantis said. “It has allowed dangerous people out of prison who have now reoffended and really, really hurt a number of people.”
This year, The New York Times reported that Mr. DeSantis and his allies saw the criminal justice bill, which Mr. Trump signed at the urging of his son-in-law Jared Kushner — and instantly regretted — as an area of political weakness, and that Mr. DeSantis had signaled he would use it in the nomination fight. The bill is unpopular with parts of Mr. Trump’s hard-core base.
But for Mr. DeSantis, assailing Mr. Trump over the First Step Act is potentially complicated. Mr. DeSantis himself voted for the first version of the bill when he was in Congress, and Trump allies have sought to highlight that fact.
“So now Swampy Politician Ron DeSanctimonious is claiming he voted for it before he voted against it,” Steven Cheung, a spokesman for Mr. Trump, said in a statement. “He sounds just like John Kerry. What a phony! He can’t run away from his disastrous, embarrassing, and low-energy campaign announcement. Rookie mistakes and unforced errors — that’s who he is.”
(Mr. DeSantis’s allies note that the version of the bill he voted for looked significantly different, and that the final version passed when he was no longer in the House.)
When Mr. Shapiro asked Mr. DeSantis about Mr. Trump’s recent criticism that crime had risen on his watch in Florida, the former president’s adopted state, Mr. DeSantis bristled and said Mr. Trump’s policies had undermined law and order.
Mr. DeSantis stepped up his attacks on his onetime ally, whom he had avoided criticizing directly for months, less than 48 hours after he entered the race in a bumpy Twitter event.
And as Mr. DeSantis seems to veer to the right on issues like crime, some of his campaign’s internal strategy is coming to light.
At a fund-raising meeting in Miami on Thursday, donors peppered Mr. DeSantis’s top campaign staff members with questions about his policy positions and how they should be presented to other Republicans, according to a leaked audio recording posted online by the website Florida Politics.
One donor raised a question about the rightward shift, to which a campaign official eventually responded, “We just got to win a primary in order to be in a general.”
The donors and officials also discussed how to talk to Republicans who support abortion rights. (Mr. DeSantis last month signed a six-week abortion ban in Florida, which contains limited exceptions, while Mr. Trump has been hesitant to support a federal ban.)
A staff member offered one possible answer.
“Abortion is safe, legal and rare in Florida,” he said, parroting a phrase coined by former President Bill Clinton, a Democrat. “It has not been banned,” he added. “It is limited.”
In his interview with Mr. Shapiro on Friday, Mr. DeSantis sought to cast himself as unwavering on illegal immigration, saying that Mr. Trump had attacked him for opposing amnesty legislation while in Congress.
He also faulted Mr. Trump for his administration’s handling of the coronavirus outbreak in 2020, especially the level of influence exerted by Dr. Fauci, the longtime top infectious disease expert and face of the federal government’s pandemic response.
Dr. Fauci, who retired in January, has been a frequent target of Republican attacks over issues like remote learning, stay-at-home orders and vaccine mandates.
“He responded by elevating Anthony Fauci and really turning the reins over to Dr. Fauci, and I think to terrible consequences for the United States,” Mr. DeSantis said. “I was the leader in this country in fighting back against Fauci. We bucked him every step of the way.”
He said that Dr. Fauci should have been fired, but Mr. Trump had honored him.
“I think the fact that Donald Trump gave Anthony Fauci a presidential commendation on Trump’s last day in office, that was a gut punch to millions of people around this country who were harmed by Fauci’s lockdowns,” Mr. DeSantis said.
A day earlier, in a post by Mr. Trump on his Truth Social platform, the former president slammed Mr. DeSantis over Florida’s response to the pandemic. He said that even former Gov. Andrew M. Cuomo of New York had done a better job limiting the loss of lives to the virus than Mr. DeSantis had.
Mr. DeSantis described Mr. Trump’s claim as “very bizarre,” and said that it suggested he would double down on his actions if there were another pandemic.