THE IMAGE OF DAD, THE SUBSTANCE OF BRO':

Allies said that reputation -- as what the Republican strategist Karl Rove called the "deepest thinker on our side" -- could prove vital in selling Mr. Bush as a presidential candidate to an electorate still scarred by George W. Bush's legacy of costly wars abroad and economic meltdown at home.

But the bookishness and pragmatism that strike mainstream Republican leaders as virtues highlight the potential difficulty that Mr. Bush may face in igniting the passions of more conservative members of the party.

The questions he grapples with most frequently, and enthusiastically, revolve around improving the effectiveness of government in areas like education, immigration and criminal justice. It is a message unlikely to electrify Tea Party and libertarian wings of his party that are openly hostile to the very idea of government.

"There is skepticism that maybe Jeb Bush wants too much government in people's lives," said Greg Mueller, a Republican strategist who has advised the presidential campaigns of Pat Buchanan, Steve Forbes and Bob Dole. "I don't know that he will ever win over the limited-government conservatives."

Mr. Bush, who has cast himself as a party reformer, seems unfazed by such critiques: At times, he has appeared to deliberately fan them by publicly castigating the leaders of his own party for adhering to failed tactics and outdated messages.

After Mitt Romney's resounding defeat in 2012, in a presidential campaign that struggled to leaven its harsh tone with an optimistic vision for governing, Mr. Bush was unsparing, warning that the Republican brand risked becoming a millstone, "associated with being anti-everything." Much of the electorate, he said, believes that "Republicans are anti-immigrant, anti-woman, anti-science, anti-gay, anti-worker."

Those who have hashed over policy and politics with Mr. Bush describe him as a conservative animated less by rigid ideology than a technocrat's quest to identify which solutions work best.

"He's not interested in proving some sort of conservative point that less government is better, though he might believe that," said Philip K. Howard, the author of influential books about law and government, who has spoken frequently with Mr. Bush. "In all of my dealings with him, he's interested in how you make government deliver effectively. What are the incentives? How do you hold people accountable?" He added: "These are the discussions, frankly, that you want government leaders to have." [...]

The approach, aides said, suffused his government, which became a hothouse for ambitious, mostly conservative policy programs. They included assigning A through F grades to public schools, offering performance bonuses to government workers, privatizing many public services  and, through billions of dollars in land purchases, locking in the conservation of the Everglades.

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