Andrew Delbanco is director of American Studies at Columbia. He is the author, most recently, of College: What It Was, Is, and Should Be (Princeton).

At the time of his first inauguration, it was widely noted that President Obama was a great admirer of Abraham Lincoln. Those who thrilled at the election of our first black president thought his decision to swear his oath on the same Bible Lincoln had used was fitting and proper. Those who distrusted him found it excessive and vain.

Four years later, the president still had Lincoln on his mind. He hosted members of Congress for a screening of Steven Spielberg’s film, and invited its screenwriter, Tony Kushner, to the White House. At his second inauguration, he quoted the greatest of inaugural addresses, in which Lincoln told the nation that the bloodbath of the Civil War, still raging as he spoke (historians have lately revised upward the estimate of battlefield deaths to three-quarters of a million), was the price demanded by God for America’s original sin of building the republic on the backs of slaves. Lincoln spoke carefully of “American slavery” rather than Southern slavery, and warned, in the phrase cited by Obama, that the price of expiation would not be met till every drop of “blood drawn by the lash” was paid in “another drawn by the sword.”

Our current president then turned to the less violent and more comfortable American story of progress through incremental reform. “Seneca Falls and Selma and Stonewall” was the alliterative phrase by which he made the turn. Reverting to his habitual appeal for bipartisanship, he spoke of what, on election night, he had called the “painstaking work of building consensus”—the sort of thing that has been a staple of inaugural speeches since Thomas Jefferson declared, after the bitter election of 1800, “We are all Republicans, we are all Federalists.”...