Lincoln, played by Daniel Day-Lewis, narrates the pivotal moments of President Abraham Lincoln’s endeavors in January 1865 to secure the passage of the Thirteenth Amendment to the United States Constitution through the House of Representatives. This amendment aimed to formally abolish slavery within the nation.

As the Civil War’s end looms on the horizon, Lincoln is eager to ensure that his 1863 Emancipation Proclamation is protected. He fears that once the war concludes, the courts might invalidate it, and that the return of slave states could jeopardize the amendment’s passage. Hence, he believes it is crucial to finalize the amendment by the end of January, eliminating the risk of re-enslavement for those already freed.

However, the optimistic vision of the amendment’s swift passage clashes with the trepidation of the Radical Republicans, who worry about its potential defeat by those determined to obstruct it. Moments of uncertainty arise, particularly among border-state Republicans, as they grapple with resolving the war before committing to abolishing slavery.

Virtually all support hinges on several Democratic congressmen, especially with many Democrats recently becoming lame ducks after their electoral defeats in the fall of 1864. While some of Lincoln’s advisors suggest delaying the amendment until the new Congress is sworn in—predictably favoring Republicans—Lincoln stands firm, determined to address the issue of slavery before welcoming the southern states back into the Union.

Lincoln counts on the steadfast support of Francis Preston Blair, the founder of the Republican Party. Blair’s influence is crucial in swaying the conservative Republicans from western and border states. As a potential Union victory feels increasingly imminent, Blair expresses a desire to initiate peace talks with the Confederate government, complicating Lincoln’s efforts, as many within the Radical Republican faction would vehemently oppose any peace that leaves slavery unchallenged.

Recognizing that he requires Blair’s backing, Lincoln acquiesces to this request, aware that many Radical Republicans are staunchly against negotiating peace unless it ensures an end to slavery. Meanwhile, Lincoln and Secretary of State William Seward (portrayed by Stephen Henderson) work tirelessly to negotiate vital Democratic votes.

Lincoln proposes targeting the lame duck Democrats, emphasizing their newfound freedom to vote without the burden of reelection in mind, positioning potential federal jobs as an inducement. Even though outright bribes are off the table, agents are discreetly contacting Democratic congressmen, hinting at jobs in exchange for favorable votes.

As preparations for the crucial vote unfold, Lincoln instructs that Confederate negotiators be kept away from Washington. Just before the vote, Thaddeus Stevens (played by Tommy Lee Jones) moderates his rhetoric on racial equality, hoping to bolster the amendment’s prospects. Unforeseen rumors surface regarding Confederate representatives in the capital, inciting calls from both Democrats and conservative Republicans to defer the voting process.

Lincoln, maintaining a delicate balance, categorically denies the presence of such envoys—technically true, as they have been barred entry—and the vote eventually proceeds, resulting in a narrow passage by a margin of two votes. Following this momentous occasion, Lincoln meets with the Confederate representatives, affirming that slavery’s restoration is unequivocally off the table as the North unites for the amendment’s ratification.

The narrative then transports us to a grave yet powerful month later, highlighting Lincoln’s presence at the battlefield in Petersburg, Virginia, where he exchanges words with General Grant. In quick succession, Grant receives General Lee’s surrender at Appomattox Courthouse, marking a significant turning point.

On the fateful evening of April 14, 1865, while Lincoln engages with his cabinet on measures to enfranchise African Americans, he is reminded of an evening planned at Ford’s Theatre. That night, as his son Tad Lincoln enjoys a performance of Aladdin and the Wonderful Lamp at Grover’s Theater, a harrowing announcement disrupts the cheers—Lincoln has been shot. The following morning, his physician confirms the tragic news of his death. The film poignantly concludes with a reflective flashback to Lincoln’s second inaugural address, encapsulating the weight of his legacy.