Indeed, one of the major themes of the older brother was energy independence, prompting the president to plead from the Detroit lectern: “For the sake of this economy, for the sake of national security, Congress needs to pass an energy plan and get it to my desk as soon as possible, so we can become less reliant on foreign sources of energy.” No 2016 presidential candidate will say anything remotely like that in an era when energy independence may be within reach.

President Bush used his Detroit speech to advocate a change in “our outdated immigration laws,” specifically deploring plans for amnesty. His brother’s vision is subtlety different, with more room for immigrants illegally in the United States to remain. “You come, you work hard, you embrace [American] values, and you’re as American as anyone who came on the Mayflower,” he said in Detroit last week.

In the past several weeks, as the younger Mr. Bush’s presidential aspirations have become clearer, he has sought to clarify his views and to separate them, slightly but unmistakably, from those of his brother. He has done so with nuance, not so much shifting his feet away from George W. Bush conservatism as shifting his posture.

The effort is less a review of his brother’s conservatism than a revelation of his own, encapsulated in remarks like this, from the Detroit speech: “I know some in the media think conservatives don’t care about the cities. But they are wrong. We believe that every American in every community has the right to pursue happiness.”