We are going to be hearing more about this notion of exceptionalism, possibly far beyond Iowa and New Hampshire and into the general election. So let’s be clear about the history — and the uses and abuses — of the vision of America as an instrument of God’s will on earth.

This sense that we are the new Israel, a chosen people, is among the most ancient and most potent of American ideas. It has informed our finest hours and some of our worst. It has given us the confidence to project our power in defense of the weak and of the innocent and the persecuted. It has sometimes fed a sense of hubris and moral self-certainty. And it is bipartisan: George W. Bush is often criticized for his religiously informed language, but it was FDR who delivered a prayer of his own composition on D-Day, and John F. Kennedy closed his inaugural address by saying that “on earth, God’s work must truly be our own.”

When the rhetoric of exceptionalism is invoked — and it often is, by Republicans and by Democrats — liberals should not roll their eyes nor should conservatives to salute blindly. A sensible way forward is for us to weigh our history and our sense of ourselves in the manner of Lincoln, who called us “God’s almost-chosen people,” and saw the nation’s story as one in which we struggled in the twilight to seek to perfect a still-imperfect union.