Mr. DeSantis’s political maneuvering and extensive national donor network have allowed him to emerge as a top Republican candidate to succeed Mr. Trump on the ballot in 2024 if the former president does not run again. The governor’s brand of libertarianism — or “competent Trumpism,” as one ally called it — is on the ascent. Seizing on conservative issues du jour like opposition to social media “censorship” and vaccine passports, he has forged strong connections with his party’s base... Mr. DeSantis has raised his profile despite lacking the gregarious personality that might be associated with an aspiring Trump successor. Unlike the former president, no one would describe the publicly unemotional and not especially eloquent Mr. DeSantis as a showman. (After a record day of coronavirus deaths in July, he offered, “These are tough, tough things to see.”) People close to him describe an un-Trump-like fondness for poring over articles in scientific journals. And, they say, do not underestimate the intellect and instinct that have repeatedly defied expectations and propelled Mr. DeSantis from Little Leaguer in middle-class Dunedin, Fla., to potential presidential contender.