On the afternoon of New Year’s Day in 1863, an exhausted President Abraham Lincoln sat down to sign the Emancipation Proclamation, freeing all slaves in the rebellious Southern states. He called it “the central act of my administration and the great event of the 19th century.” That was not an exaggeration.

But the president had a problem. After hours of shaking hands during an open house at the White House, his hand was cramped and trembling. “My arm is stiff and numb,” he told a few witnesses, and he worried that his signature would be seen as shaky. He carefully inscribed his name on the document that he said “knocked the bottom out of slavery.”

How Lincoln got to that point, when he could make the demise of slavery a Union goal in the Civil War, is the subject of David Von Drehle’s latest book. It’s a compelling, sharply written narrative of the events of 1862, when the odds were against the survival of the Union itself.

This was the year that saw the Civil War explode from a few small battles to the first total war of the Industrial Age, with carnage that was unimaginable when Southern states seceded the year before. As the Union’s military efforts faltered, many in the North soured on the war effort. Congress was divided on what to do. The Supreme Court opposed the president. England and France threatened to enter the war on the side of the South.

Navigating the treacherous events of 1862 tested all of Lincoln’s political skills. Von Drehle, a former Miami Herald reporter who is now Time magazine’s editor-at-large, keeps the focus on the “evanescent character” of Lincoln as he settled on a political and military strategy, maintaining a fractious coalition at home while artfully keeping foreign powers at bay.

Lincoln often said slavery was doomed, but he was a gradualist and pragmatist on how to end it. He could not rush into it or risk losing the border slave states of Maryland and Kentucky. His keen sense of timing and political maneuvering — and the bloody battle of Antietam, which repulsed Confederate forces — gave him the space and time to issue the Emancipation Proclamation.

Amid the shelves of Civil War tomes, Rise to Greatness stands out as a brisk, compact history of Lincoln’s evolution as a leader. Von Drehle persuasively calls 1862 “the hinge of American history, the decisive moment at which the unsustainable compromises of the founding generations were ripped up in favor of a blueprint for a much stronger nation.”

This book may get a boost from the popularity of Steven Spielberg’s new film Lincoln; Rise to Greatness could function as a prequel on how a nation torn apart by slavery and war found a new path. There is no preachiness in Von Drehle’s portrait of Lincoln, a leader who was riven by doubts as he governed day by day through an unprecedented crisis.

The president made mistakes. He persisted in the fantasy of sending freed slaves to colonize other lands. He dithered on some decisions and stumbled on some of his appointments. He spent years finding good generals to win the war.

Under pressure from abolitionists and other critics willing to keep slavery, Lincoln’s close aides described him as “oscillating between misery and anger as the public badgered him over his seeming fecklessness.”

But in finding a way to save the Union and end slavery, the president achieved the greatness he unabashedly sought. “Lincoln’s dream was to be the rare individual whose name and story would live on,” Von Drehle concludes, and this book shows how he did just that.

Frank Davies is a writer in northern Virginia.