Independence Day arrives this year during a period of intense political polarization, anger and distrust, potentially jeopardizing the ideals for which the American Revolution was fought.


That’s a problem, but it also signals an opportunity. Nations benefit from the unifying effects of shared memories — especially if those memories reflect a commitment to ideals. The revolution was inspired by two such ideals: self-government and human liberty.


To understand the current importance of that claim, a good place to look is a speech by Abraham Lincoln - not by the president who emphasized the better angels of our nature, but by a largely unknown 28-year-old, speaking in 1838 before the Young Men’s Lyceum in Springfield, Illinois under the ambitious title The Perpetuation of Our Political Institutions.


Even as a young man, Lincoln was obsessed by founding principles, and as he would 25 years later at Gettysburg, he focused on the foundations of the American experiment in self-government.


The occasion for the speech was what Lincoln saw as a serious danger, not from abroad but from “amongst us.” Two weeks before, parts of the nation had reeled from a gruesome murder in St. Louis. As Lincoln put it:


“A mulatto man, by the name of McIntosh, was seized in the street, dragged to the suburbs of the city, chained to a tree, and actually burned to death; and all within a single hour from the time he had been a freeman, attending to his own business, and at peace with the world.”


Lincoln insisted that black lives matter. Decades before ratification of the 14th Amendment to the Constitution and its equal protection clause, which followed the Civil War, Lincoln insisted on the equal protection of the laws.


But Lincoln had a broader claim, involving the importance of respect for the law, and of inculcating it in people’s hearts. That idea should “be taught in schools, in seminaries, and in colleges; let it be written in Primers, spelling books, and in Almanacs; let it be preached from the pulpit, proclaimed in legislative halls, and enforced in courts of justice.” He argued that reverence for the law, and for the rule of law, should become “the political religion of the nation” (the italics are his).


Lincoln had an even larger argument. To the Young Men’s Lyceum, he recalled the American Revolution itself, which he described as a bold effort “to display before an admiring world, a practical demonstration of the truth of a proposition, which had hitherto been considered, at best no better, than problematical; namely, the capability of a people to govern themselves” (again, Lincoln’s italics).


The American experiment in self-government was succeeding. But its future was hardly guaranteed. Lincoln worried over the emergence of a leader who “thirsts and burns for distinction,” who might “set boldly to the task of pulling down.” Lincoln described this as “a probable case, highly dangerous.”


At that point, Lincoln looked backward to the revolution itself. Writing 62 years after the Declaration of Independence, he argued that the time had come to move past the emotional fervor that animated the war effort and to cultivate reason instead.


Americans, he declared, should understand “the powerful influence which the interesting scenes of the revolution had upon the passions of the people as distinguished from their judgment.” Focused as we were on defeating Britain, “the basest principles of our nature, were either made to lie dormant, or to become the active agents in the advancement of the noblest cause—that of establishing and maintaining civil and religious liberty.”


The problem was that “this state of feeling must fade, is fading, has faded, with the circumstances that produced it.” What was until recently a living history was starting to disappear, along with the people who had experienced it. Memories had dimmed.


In Lincoln’s account, passion “will in future be our enemy.” Reason, by contrast, “must furnish all the materials for our future support and defense.” Those materials must be molded into “a reverence for the constitution and laws.”


Lincoln delivered the Lyceum Address 179 years ago, which means that nearly three times as many years separate us from his remarks as separated those remarks from the Declaration of Independence.


To many of us, July 4 is more about fireworks, family and a day off than about shared national memories, or the capacity for self-governance or civil and religious liberty.


But with Honest Abe, let’s step back and focus on those things. For all the contemporary challenges, Americans retain them. Lincoln was right: They deserve our reverence.


Cass Sunstein is a Bloomberg View columnist. For more columns from Bloomberg View, visit http://www.bloomberg.com/view.