Seven states had left the Union. Fort Sumter needed to be resupplied. Washington was in upheaval, sharpshooters were deployed to the roofs of buildings, a light-artillery battalion was installed on Capitol Hill. It was in this atmosphere, 150 years ago this week, that Abraham Lincoln took the oath of office.

In more than two centuries of turning points — George Washington’s victory at Yorktown, Woodrow Wilson’s decision to enter a great European war, Franklin Roosevelt’s unveiling of the New Deal, the attacks of 1941 and 2001 — this may have been America’s greatest, most dangerous, most portentous. At stake on March 4, 1861, was more than the survival of the nation. At stake were the values that created the nation.

In the hands of history was a man with little formal education, no conventional religion, no executive experience, only two years’ time in the House of Representatives, a distracting and difficult family situation — but with a deep understanding of the land, a natural mastery of language, an intuitive insight into human nature and an unfailing comprehension of the consequences of his thoughts and deeds.

He knew the country and he knew his mind. He loved the Union, deplored slavery, and before his first term was over would determine that the survival of the one required the obliteration of the other. A man who had not done much with his first 52 years would accomplish two great things in his last four years. He would save the United States and, by ending slavery, he would make it worth saving.

This was a moment like no other in our history. Handing the presidency over to Lincoln was Pennsylvania’s only chief executive, poor James Buchanan, one of America’s great secretaries of state and perhaps its worst president, a man who had done little to forestall war and less to understand the great forces of his time. “He frequently examines the Constitution, and the more he looks at it the less he finds in it,” the Times of London wrote, adding: “The war which he could not make he now finds that he has no power to prevent.”

Joining the new president in his administration was William H. Seward, who, as a showy public figure and relentless attention-seeker, was Lincoln’s opposite in character but, fortunately for the nation, was Lincoln’s equal in intelligence. And while it is tempting — indeed, it would be Seward’s fondest wish — to say that together they created one of the most significant inaugural addresses in history, the remarks that Lincoln uttered against the greatest metaphorical backdrop in America’s pageant (the scaffolding on the Capitol, symbolic of the unfinished nature of the country) were pure Lincoln.

Lincoln had left Springfield, Ill., three weeks earlier with a draft of his speech, the product, wrote Douglas L. Wilson, an expert on Lincoln, of “considerable drafting and revision.” The story of how Seward worked over Lincoln’s draft and provided what Seward’s son called “suggestions for a closing paragraph” is well known, but what is remarkable is how the president-elect salvaged words Seward abandoned and reshaped them into a statement all his own — one that now is all our own. The final paragraph of the final version reads this way:

“I am loath to close. We are not enemies, but friends. We must not be enemies. Though passion may have strained, it must not break our bonds of affection. The mystic chords of memory, stretching from every battlefield and patriot grave to every living heart and hearthstone all over this broad land, will yet swell the chorus of the Union, when again touched, as surely they will be, by the better angels of our nature.”

The paragraph that preceded that coda for the ages is instructive. Lincoln opened it by underlining what he would disprove — the very American notion that the will of the people is more important than the will of a national leader. “In your hands, my dissatisfied fellow countrymen, and not in mine,” he said, “is the momentous issue of civil war.”

There was, of course, a kernel of truth in that, as Hosni Mubarak could testify. But, perhaps even more so than Franklin Roosevelt, Lincoln would reshape the presidency into what FDR called it — pre-eminently a place of moral leadership.

To his countrymen, Lincoln’s address represented an end to his great post-election silence. Only days before his inauguration, Frederick Douglass wrote, hopefully, of Lincoln’s “stately silence during these last tumultuous and stormy three months, his stern refusal thus far to commit himself to any of the much-advocated schemes of compromise, his refusal to have concessions extorted from him under the terror instituted by thievish conspirators and traitors.”

We know what Lincoln’s remarks mean to us now. They were the first indication that the new president, characterized as a baboon, castigated as a backwoods babbler more suited to the splitting of rails than the adjudication of hard political problems, was more than presidential. He was — to choose a word at odds with our traditions and applicable to only one other president, George Washington — regal.

“Beyond the immediate hearers was the vast unseen audience that would read the address in cold print,” wrote Carl Sandburg in his lyrical if not exactly historical biography of Lincoln. “Never before in New York had such crowds waited at newspaper offices and jammed and scrambled for the first sheets wet from the press. In its week of delivery, it was the most widely read and closely scrutinized utterance that had ever come from an American president.”

American presidents have delivered 56 inaugural addresses and only five are quoted today. One is from Jefferson, one from Franklin Roosevelt, one from John F. Kennedy. Two are from Lincoln. His remarks a century and a half ago are mystic chords of memory, delivered at the most frightful juncture in our history.

— David Shribman is executive editor of the Pittsburgh Post-Gazette.