Bush is less concerned about the opinions of his current critics than those of future generations, Caldwell said. Last month, Bush visited an American government class at Southern Methodist University to lecture to a group of 19- and 20-year-olds who were not old enough to vote for or against him. His appearance was planned one week in advance but kept secret until the moment he walked into a classroom flanked by the university president, vice president, three personal aides and the Secret Service. The 30 students were instructed to turn off their cellphones and put away their cameras until the end of class.

Bush spoke for the first 10 minutes about his presidential center and his new life in Dallas. The students, most of whom had described themselves as conservative on a class questionnaire at the beginning of the semester, treated Bush with respect, even reverence. He asked for questions. One student raised a hand.

How did you make your decisions in office?

The classroom windows were covered with white paper to prevent outsiders from peering in. Secret Service agents were standing guard. The students were too star-struck to take notes. Bush stood at the center of the classroom, at home in the 33 percent, and offered an early summation of his presidency.

You make your decisions based on principles, he said. And you never worry about popularity or polls.