“[T]he struggle over slavery and racial injustice that did result in civil war. Here, too, the disputes were not merely about means, but about ends — about fundamental matters of right and wrong. And although the war, after consuming the lives of nearly three-quarters of a million people, ended after four years, the struggle went on for more than a hundred more, and we are still living with its aftershocks today.”

Remarks at Bowie State University ceremony (17 May 2013) http://www.whitehouse.gov/the-press-office/2013/05/17/remarks-first-lady-bowie-state-university-commencement-ceremony
2010s
Context: But today, more than 150 years after the Emancipation Proclamation, more than 50 years after the end of 'separate but equal', when it comes to getting an education, too many of our young people just can’t be bothered. Today, instead of walking miles every day to school, they're sitting on couches for hours playing video games, watching T. V. Instead of dreaming of being a teacher or a lawyer or a business leader, they're fantasizing about being a baller or a rapper. Right now, one in three African American students are dropping out of high school. Only one in five African Americans between the ages of 25 and 29 has gotten a college degree; one in five.

Native Son (1940)

(A.J. Broomhall. Hudson Taylor and China’s Open Century, Book Five: Refiner’s Fire. London: Hodder and Stoughton and Overseas Missionary Fellowship, 1985, 285).

A Prescription for Hope (1985)
Context: The hope of a benevolent civilization was shattered in the blood-soaked trenches of the First World War. The "war to end all wars" claimed sixteen million lives, and left embers which kindled an even more catastrophic conflagration.
Over the sorry course of 5,000 years of endless conflicts, some limits had been set on human savagery. Moral safeguards proscribed killing unarmed civilians and health workers, poisoning drinking waters, spreading infection among children and the disabled, and burning defenseless cities. But the Second World War introduced total war, unprincipled in method, unlimited in violence, and indiscriminate in victims. The ovens of Auschwitz and the atomic incineration of Hiroshima and Nagasaki inscribed a still darker chapter in the chronicle of human brutality. The prolonged agony which left 50 million dead did not provide an enduring basis for an armistice to barbarism. On the contrary, arsenals soon burgeoned with genocidal weapons equivalent to many thousands of World War II's.
The advent of the nuclear age posed an unprecedented question: not whether war would exact yet more lives but whether war would preclude human existence altogether.

1990s, 3001: The Final Odyssey (1997)

Source: Afterworlds

The Great Indian Novel (1989)

Remarks by the President on the Iran Nuclear Deal at American University in Washington, D.C. (August 05, 2015) https://www.whitehouse.gov/the-press-office/2015/08/05/remarks-president-iran-nuclear-deal
2015
Context: But how can we in good conscience justify war before we’ve tested a diplomatic agreement that achieves our objectives; that has been agreed to by Iran; that is supported by the rest of the world; and that preserves our options if the deal falls short? How could we justify that to our troops? How could we justify that to the world or to future generations? In the end, that should be a lesson that we’ve learned from over a decade of war. On the front end, ask tough questions. Subject our own assumptions to evidence and analysis. Resist the conventional wisdom and the drumbeat of war. Worry less about being labeled weak; worry more about getting it right.

"The Civil War in 'Postracial' America" https://web.archive.org/web/20111001073757/http://ericfoner.com/articles/101011nation.html (10 October 2011), The Nation
2010s