Michael Gerson

That story has many themes, but one major challenge: a desperate, sometimes bloody, search for unity. The consequential inaugurals confront the issue directly. Presidents before Lincoln attempted to maintain a political union of fractious states. Once shattered, warned Franklin Pierce, "no earthly power or wisdom could ever reunite its broken fragments." Lincoln set out the ideal of a spiritual union -- a union of idealism and of shared suffering -- that transcended race and took a century to even partially achieve. Presidents in the tradition of Woodrow Wilson and Franklin Roosevelt asserted a national unity founded on democratic idealism, in a world gone mad from imperialism, racism and ideology. "The democratic aspiration is no mere recent phase in human history," said FDR in his third inaugural. "It is human history."

In an earlier inaugural speech, Roosevelt observed, "In every land there are always at work forces that drive men apart and forces that draw men together." Those forces remain at work. Through the tumults of the '60s and '70s, America experienced divisions that turned generation against generation. Today our cultural and political differences seem mainly expressed by derision, in a kind of spiritual secession from one another.

It is the primary purpose of presidential leadership to be a force that draws us together -- to declare, as Jefferson did, that we are "brethren of the same principle," to state and plead, as Lincoln did, that "We are not enemies, but friends. We must not be enemies." The origin of this unity for Americans is not an accident of blood or birth, but certain shared moral affirmations about the rights and dignity of all men and women -- assertions contained in the Declaration of Independence, and uncontained in their global influence. The existence of those rights imposes duties on government -- and creates obligations of citizens to each other.

In an inaugural address equal to his moment, Obama will summarize a historical achievement he already symbolizes -- and explain how this flawed, grand, God-shaken story moves forward to include everyone. This hope of unity is stronger than all the hypocrisy of our past, and louder than the clank of chains. It led men and women to travel on immigrant ships and the Underground Railroad -- and it explains the amazing journey from the Yellow House to a white one just down the street.

Michael Gerson

Michael Gerson writes a twice-weekly column for The Post on issues that include politics, global health, development, religion and foreign policy. Michael Gerson is the author of the book "Heroic Conservatism" and a contributor to Newsweek magazine.
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