From a Wall Street Journal column by Peggy Noonan:

First spouses have profound cultural power. When Mrs. Kennedy had Pablo Casals play at the White House, she was saying high art not only has a revered place in the people’s house, it has a high role in the people’s lives. Lady Bird’s cause was getting America to clean up its physical environment. When she became first lady in 1963 we were a nation that threw the Coke bottle out of the car onto the country road. By the time she left, somehow we didn’t.