“At a moment when it seems that our democracy is more defined by our discord and our dysfunction than by our own values and principles, let me begin by noting the somewhat obvious point that these offices that we hold are not ours indefinitely. We are not here simply to mark time. Sustained incumbency is certainly not the point of seeking office and there are times when we must risk our careers in favor of our principles. Now is such a time.It must also be said that I rise today with no small measure of regret. Regret because of the state of our disunion. Regret because of the disrepair and destructiveness of our politics. Regret because of the indecency of our discourse. Regret because of the coarseness of our leadership.”

54 min 55 sec
Cosmos: A Personal Voyage (1990 Update), Journeys in Space and Time [Episode 8]
Context: Those worlds in space are as countless as all the grains of sand on all the beaches of the earth. Each of those worlds is as real as ours and every one of them is a succession of incidents, events, occurrences which influence its future. Countless worlds, numberless moments, an immensity of space and time. And our small planet at this moment, here we face a critical branch point in history, what we do with our world, right now, will propagate down through the centuries and powerfully affect the destiny of our descendants, it is well within our power to destroy our civilization and perhaps our species as well. If we capitulate to superstition or greed or stupidity we could plunge our world into a time of darkness deeper than the time between the collapse of classical civilization and the Italian Renaissance. But we are also capable of using our compassion and our intelligence, our technology and our wealth to make an abundant and meaningful life for every inhabitant of this planet.

Barack Obama’s Remarks in St. Paul http://www.nytimes.com/2008/06/03/us/politics/03text-obama.html (3 June 2008)
2008

“What is liberal education,” pp. 7-8
Liberalism Ancient and Modern (1968)

2000s, 2001, First inaugural address (January 2001)
Context: We must live up to the calling we share. Civility is not a tactic or a sentiment. It is the determined choice of trust over cynicism, of community over chaos. And this commitment, if we keep it, is a way to shared accomplishment. America, at its best, is also courageous. Our national courage has been clear in times of depression and war, when defending common dangers defined our common good. Now we must choose if the example of our fathers and mothers will inspire us or condemn us. We must show courage in a time of blessing by confronting problems instead of passing them on to future generations.

Address to the United Nations General Assembly, 17 September 2005 (excerpts)

For the American people can no more meet the demands of today’s world by acting alone than American soldiers could have met the forces of fascism or communism with muskets and militias. No single person can train all the math and science teachers we’ll need to equip our children for the future, or build the roads and networks and research labs that will bring new jobs and businesses to our shores. Now, more than ever, we must do these things together, as one nation and one people.
2013, Second Inaugural Address (January 2013)

Source: Your Best Life Now: 7 Steps to Living at Your Full Potential

1950s, Address at the Philadelphia Convention Hall (1956)