None of that is easy, but, with significant backing from Republican donors, it’s doable.

More fundamentally, a presidential candidate needs a personal narrative that dovetails with his political message in a way that candidates for lesser offices simply don’t. Without one, they rarely succeed. Barack Obama was a groundbreaking African American candidate for a country that needed the audacity of hope. Donald Trump was the outsider billionaire for a country that needed to be made great again.

What is DeSantis? He has spent the last several months talking about his record in Florida more than about himself, which is admirable in a way — but policies don’t tell a story. At the moment, the average Republican knows little or nothing about his Yale baseball career, his military service during the war on terrorism, his wife’s fight against breast cancer or his life as a very busy father of three young children. In a recent trip through Iowa, his wife, Casey, talked in a more personal mode about their life together; there will have to be more of that.

Much has been made lately of DeSantis’s standoffishness. Even if this has been exaggerated, there’s no doubt that he isn’t a Bill Clinton-style politician who feeds off people. For him, retail politics is clearly work, and he needs to do it. His team now has him staying after events, to glad-hand. He’ll have to do it wherever he goes, without showing any boredom or irritation, lest he confirm the idea that he lacks a personal touch.

He’ll need to plant his feet firmly on tricky issues in a Republican primary: What does he think of the legitimacy of the 2020 election? Where he is now on entitlement reform? Perhaps his worst moment in the pre-announcement phase was his backtracking on a poorly drafted statement calling the Ukraine war “a territorial dispute,” which dismayed both G.O.P. supporters and opponents of large-scale aid to Ukraine.

Then, of course, there’s the big, looming question of how to respond to Trump’s attacks. Ignoring them, as DeSantis has mostly done this spring, seems weak; responding risks playing Trump’s game. No Republican has yet figured out this conundrum, with the exception of Gov. Brian Kemp of Georgia.