At Robert Kennedy's funeral his brother Edward quoted from a recent presidential campaign speech of his:
All of us will ultimately be judged and as the years pass we will surely judge ourselves, on the effort we have contributed to building a new world society and the extent to which our ideals and goals have shaped that effort.
The future does not belong to those who are content with today, apathetic toward common problems and their fellow man alike, timid and fearful in the face of new ideas and bold projects. Rather it will belong to those who can blend vision, reason and courage in a personal commitment to the ideals and great enterprises of American Society.
Our future may lie beyond our vision, but it is not completely beyond our control. It is the shaping impulse of America that neither fate nor nature nor the irresistible tides of history, but the work of our own hands, matched to reason and principle, will determine our destiny. There is pride in that, even arrogance, but there is also experience and truth. In any event, it is the only way we can live.
Thanks to Stephen Pinker and his 2002 book 'Blank Slate'.