If I recall correctly, Joseph Anthony Califano, Jr., who served as Secretary of Health, Education, and Welfare during the Carter Administration, felt obligated to quit smoking in order to set an example in his new post, given the emerging evidence of adverse health effects of tobacco. I was on the medical staff of Gracie Square Hospital, a private psychiatric hospital in New York City, at the time, and an anti-tobacco activist myself, so I was not about to miss the opportunity to hear him speak at the hospital where there was still a cigarette vending machine in the patients' day room upstairs, and patients smoked freely during their hospital stays.
Mr. Califano told a story of driving through suburban Maryland with his teenage son soon after his appointment. He said his son knew of his dad's frustration in attempting to get Americans to give up smoking. Attempting to console him as they passed a high school, his son drew attention to a group of youngsters sitting on the steps at the school entrance. He said something like this, "Don't feel so bad, Dad. A few years ago every one of those kids would have been smoking a cigarette. Now they just have one, and they're passing it around."