Garry Wills has a memorable essay on Obama and Lincoln:
In preparing his speech, Obama had called and talked to the hurt and the survivors. He could tell their personal stories. Michelle Obama invited the family of the murdered nine-year-old to visit her in the White House. Obama came to the speech from the bedsides of those who had been wounded. Their message to him was one of dedication: “They believed, and I believe, that we can be better.” This rang a bell with me.
It reminded me of the lesson of the fallen that Lincoln took from Gettysburg“that from these honored dead we take increased devotion to that cause for which they gave the last full measure of devotion.” At Gettysburg Lincoln might have been expected to defend the North and blame the Southwhich is what Edward Everett did in the speech preceding his. Rather, the bulk of his speech was given to praising the dead and urging others to learn from them.