At moments of institutional conflict and uncertainty, Americans naturally turn to the Constitution. But at times of anger, division and national self-doubt, the best American leaders have helped us turn to a different document: the Declaration of Independence. That few seem to be doing so now — in our season of division and doubt — is another sign that we lack real leaders.

The Declaration is an odd source of national pride since it can be properly read only in a spirit of humility. It refers to a transcendent order of justice and human dignity that existed prior to the nation — and that exposed the nation’s horrifying hypocrisies. (“How is it,” taunted Samuel Johnson, “that we hear the loudest yelps for liberty among the drivers of Negroes?”) “We hold these truths” makes us vulnerable to the judgment of those truths.

American independence, of course, involved more than humility. It was an act of defiance rooted in an arm-long list of grievances. In Worcester, Mass., after the Declaration was signed, patriots drank to the toast: “Perpetual itching without the benefit of scratching to the enemies of America.”

But, as Abraham Lincoln noted, the Declaration could have established national independence without its second paragraph about the human rights to “life, liberty and the pursuit of happiness.” “The assertion that ‘all men are created equal,’ ” Lincoln argued, “was of no practical use in effecting our separation from Great Britain.” As he saw it, the Founders, while constrained by the political realities of their time, set out a non-arbitrary, timeless truth “for future use.”

“They meant simply to declare the right,” said Lincoln, “so that the enforcement of it might follow as fast as circumstances should permit. They meant to set up a standard maxim for free society, which should be familiar to all, and revered by all; constantly looked to, constantly labored for . . . even though never perfectly attained.”

Why is that maxim so important? At one level, Lincoln’s answer was bluntly practical. If liberty is denied to anyone, it could eventually be denied to you. “And when you have stricken down the principles of the Declaration of Independence,” he said, “and thereby consigned the Negro to hopeless and eternal bondage, are you quite sure that the demon will not turn and rend you? Will not the people then be ready to go down beneath the tread of any tyrant who may wish to rule them?”

But Lincoln also saw the Declaration as the embodiment of a moral ideal. “It was not the mere matter of the separation of the colonies from the motherland; but something in that Declaration giving liberty, not alone to the people of this country, but hope to the world for all future time. It was that which gave promise that in due time the weights should be lifted from the shoulders of all men, and that all should have an equal chance.”

By definition, America can’t be a normal nation. It stands for more than getting and keeping. Its greatness is a greatness of spirit. And its failures — such as slavery, segregation and the shameful treatment of Native Americans — are not only legal but also spiritual failures. They are blasphemy against our country’s creed.

Does anyone think or talk like this now? They need to. There is so much dehumanization in our politics, and the main role of the Declaration is humanization. Its ideals are desperately needed and roundly ignored.

How do we measure our loss? It might be a useful exercise to take political arguments and apply the Declaration as a kind of suffix. So: We should fear Latino migrants as gang members and murderers . . . and all men and women are created equal. Or: Muslims are a threat and should be kept out of the country . . . and all men and women are created equal. Or: Spending on AIDS treatments for foreigners is a waste . . . and all men and women are created equal. Or: The human cost of a failing health or education system doesn’t matter . . . and all men and women are created equal. Or: Human beings can be dismembered up to the moment before birth . . . and all men and women are created equal.

When our founding ideals are forgotten, it is the vulnerable and powerless who suffer first and worst. Lincoln accused politicians who dismiss or play down the Declaration of “blowing out the moral lights around us.” When someone calls us back to that faded document, and begins to rekindle America’s conscience, it will be a sign we have found a real leader again.

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