In the final paragraphs of Heirs of the Founders, H. W. Brands summarizes the critical years that preceded the Civil War and reminds us — as if we need reminding — of the deep division that remains:

The deaths of Calhoun, Clay and Webster appeared less uncannily timed than the same-day deaths of Jefferson and Adams on the fiftieth anniversary of the Declaration of Independence. Nothing could match that earlier coincidence. But if the passing of the two founders in 1826 had symbolized the end of the first generation of America’s nationhood, the demise of the three senators amid the controversy surrounding the Compromise of 1850 marked the end of the second.

The founders had won freedom for America and created the Union of the states; their heirs had confirmed freedom and guided the Union through four decades of crisis. Neither group felt that its task was complete; American self-government was always a work in progress. Jefferson had shuddered at what the fight over the Missouri Compromise portended; Clay, Calhoun and Webster understood that the Compromise of 1850 might purchase time but guaranteed no final resolution of the struggle between the sections.

In their deaths the country honored the three as it had not always done in their lives. Henry Clay became the first American to lie in state in the Capitol; his funeral train took the long way to Lexington, looping north to Philadelphia and New York before turning west. Hundreds of thousands of mourners lined the route and paid their respects as the black-veiled car rolled by. …

The honors accorded John Calhoun were fittingly sectional. His remains were carried to Richmond; thousands journeyed to the Virginia capitol to pay their respects. Another train took him to Charleston, where thousands more viewed the casket in the city hall. He was interred in a churchyard not far from the harbor.

Daniel Webster, having died in his home, was buried there and required no transport. But half of Massachusetts, it seemed, clogged the railways and roads to Marshfield to acknowledge their debt to the state’s most famous adopted son.…

Americans felt great loss in the aftermath of the three deaths, but the nation required several years to determine just what the loss entailed. The Whig party fell to pieces, deprived of the leadership of Clay and Webster. A successor coalition, taking the name of Jefferson’s party, organized Northern Whigs and free-soil Democrats into a new Republican party, which was explicitly antislavery and effectively anti-Southern. The ghost of Henry Clay shook his head in sorrow, while John Calhoun’s specter nodded grimly at this fulfillment of his prophecy of escalation against the South.

The sectional contest took a bloody turn after Stephen Douglas pushed a bill through Congress repealing the Missouri Compromise, the more swiftly to settle Kansas and Nebraska. John Calhoun’s shade again nodded, this time in approval. Slaveholders poured into Kansas from neighboring Missouri; antislavery activists rushed to counter them. The result was an irregular war between zealots of the two sides. Among the antislavery militants was the charismatically monomaniacal John Brown, who led a band of followers in a brutal murder of several pro-slavery settlers.

While Kansas bled, the federal courts heard a case involving a slave named Dred Scott. The eventual verdict by the Supreme Court confirmed John Calhoun’s judgment that slaveholders could not be barred from taking their slaves into the federal territories. The Missouri Compromise had been unconstitutional all along.

The South celebrated; many in the North despaired. But the South was the side despairing after John Brown and a larger band of antislavery militants staged a raid on the federal arsenal at Harpers Ferry, Virginia, with the aim of inciting a slave rebellion. The mission failed; the rebellion never materialized. Brown was captured, tried and executed. Yet in much of the North he was treated as a martyr, one who did what other abolitionists simply talked about. The South was aghast: a murderer made into a saint? Never had the gulf between North and South yawned wider.

Within weeks of the tenth anniversary of the Compromise of 1850, Abraham Lincoln was elected president on a Republican ticket and a Republican platform. Lincoln received not a single electoral vote from a Southern state. Southerners interpreted the outcome as proof that the federal government was irretrievably in hostile hands. South Carolina finally made good on John Calhoun’s repeated threats to secede. Six other slave states followed. When Lincoln resisted secession and attempted to resupply Fort Sumter in Charleston’s harbor, the Civil War began—within rifle shot of Calhoun’s grave.

In battling the legacy of Calhoun, Lincoln looked to Henry Clay and Daniel Webster. Lincoln had been born in Kentucky while Clay was launching his career; he took notes on Clay’s climb to national prominence as he himself calculated how to advance in the political world. Lincoln called Clay “my beau-ideal of a statesman, the man for whom I fought all my humble life.” When Lincoln learned, in Springfield, Illinois, that Clay had died, he organized a memorial for his hero and insisted on giving the eulogy. “Mr. Clay’s predominant sentiment, from first to last, was a deep devotion to the cause of human liberty, a strong sympathy with the oppressed everywhere and an ardent wish for their elevation,” Lincoln said.

To be sure, Clay had countenanced slavery. “Mr. Clay was the owner of slaves. Cast into life where slavery was already widely spread and deeply seated, he did not perceive … how it could be at once eradicated, without producing a greater evil, even to the cause of human liberty itself.” Yet Clay’s tolerance was nothing more than a temporary nod to reality. “He was ever, on principle and in feeling, opposed to slavery.” Lincoln accepted Clay’s pragmatic belief that progress came in steps. And he endorsed unreservedly Clay’s central conviction that the Union was the prerequisite of all that America had done and could do on behalf of liberty.

Lincoln didn’t know, as he concluded his eulogy for Clay, how aptly his prayer for Clay would become a prayer for himself. “Henry Clay is dead,” Lincoln said. “His long and eventful life is closed. Our country is prosperous and powerful. But could it have been quite all it has been, and is, and is to be, without Henry Clay? Such a man the times have demanded, and such, in the providence of God, was given us….”

Where Henry Clay furnished Lincoln the philosophy of democratic politics, Daniel Webster gave him the words…. He edited Webster’s formulation of democracy—“the people’s government; made for the people; made by the people; and answerable to the people”—into “government of the people, by the people, and for the people.” And when, in the same Gettysburg address, Lincoln tied the fate of liberty, by then including freedom for the slaves, to that of the Union, he echoed Webster’s ringing affirmation: “Liberty and Union, now and forever, one and inseparable!”

The equation of liberty and the Union was the central article of faith of Webster and Clay, and of Lincoln. It was what separated them from John Calhoun, who perceived liberty—for the states, and specifically for slaveholders in the Southern states—as increasingly threatened by the Union. Liberty and Union, said Clay and Webster. Liberty or Union, said Calhoun.

This was what the struggle came down to during the lives of the three. And it was the heart of the struggle they bequeathed to the next generation of Americans. Lincoln and the Union army, at great cost, assured the triumph of Clay and Webster over Calhoun and the Confederacy.

Yet the struggle persisted. Slavery was its most salient aspect at the midpoint of the nineteenth century, but the contest between the states and the national government had hinged on other issues at other times: freedom of speech in 1798, war powers in 1814, the tariff in 1833. So it wasn’t surprising that the struggle outlived slavery. Clay and Webster, with Lincoln’s help, won the argument that the Union must be unbroken, but Calhoun’s insistence on the need for balance between the states and the nation found adherents on matters that ranged, during the next several generations, from civil rights and business regulation to school funding and the environment.

The struggle originated with the founders. It continued with their heirs. It is with us still.