On the morning of President Lincoln’s first inauguration, March 4, 1861, the Senate debated passage of the 13th Amendment. Its ratification would lay to rest the question of slavery, unify the nation, and help fulfill the promise of “a more perfect Union” established in the Preamble. Future Secretary of State, William Seward, and Lincoln’s political accomplice Thurlow Weed lobbied reluctant Senators for their support. The maneuvering paid off: the Senate approved the Amendment by a single vote margin. The Amendment read,

No amendment shall be made to the Constitution which will authorize or give to Congress the power to abolish or interfere, within any State, with the domestic institutions thereof, including that of persons held to labor or service by the laws of said State.

Civil War historian Daniel Crofts’s Lincoln and the Politics of Slavery: The Other 13th Amendment and the Struggle to Save the Union presents the history of a 13th Amendment radically different from the one adopted in 1865, a version that would have forbidden the federal government from amending the Constitution to outlaw slavery. Crofts argues that the 13th Amendment that did not become part of the Constitution represented the pro-Union rather than the pro-slavery conviction of many Democrats and Republicans and counted newly inaugurated President Lincoln among its supporters.

Antebellum America was not uniformly abolitionist. Even Radical abolitionist Thaddeus Stevens acknowledged the legality of slavery in the Southern states. Unlike Frederick Douglass or Lysander Spooner, the antebellum Lincoln was a moderate conservative whose public rhetoric never advocated tampering with the institution where it legally existed.

Crofts’ account of the maneuverings in the House and Senate to advance some version of a guarantee to the South that slavery would continue is among the great descriptions of politics on the eve of the War. The amendment came under fire from outraged Republicans, who did not give it a majority in either chamber, and the remaining Southerners, who regarded it as an insult. In his first inaugural address, given just hours after the amendment’s approval, Lincoln seemingly offered his support:

I understand a proposed amendment to the Constitution—which amendment, however, I have not seen, has passed Congress, to the effect that the federal government, shall never interfere with the domestic institutions of the States, including that of persons held to service. To avoid misconstruction of what I have said, I depart from my purpose not to speak of particular amendments, so far as to say that, holding such a provision to now be implied constitutional law, I have no objection to its being made express, and irrevocable.

Crofts’ Lincoln “undoubtedly worked behind the scenes to get the amendment passed.” Yet for all the impressive detail and speculation Crofts presents, he misses the purpose of Lincoln’s endorsement of this early version of the 13th amendment. Interpreting this speech as an unqualified support misrepresents Lincoln’s intention. Having “no objection” did not mean Lincoln, the shrewd, careful lawyer, was conferring an endorsement. He had made ratification of the amendment more unlikely with his earlier observation that “the convention mode [of amending the constitution] seems preferable, in that it allows amendments to originate with the people themselves, instead of only permitting them to take, or reject, propositions, originated by others….” A convention would underscore the unity of the states, an unlikely event given secession.

Lincoln likely gave his support because he had nothing to gain by his opposition. The Confederate attack on Fort Sumter ended any hope that the amendment would prevent war. Nonetheless, its ratification in the border slave states of Kentucky, Ohio, Maryland, and West Virginia by February 1862 showed the role it played in Unionist thinking.

Slave holding interests historically dominated the Senate, the presidency, and the Supreme Court in the antebellum years. The weight of the 3/5 clause also gave the South disproportionate influence in the House. Crofts shows how the secession crisis played out in Congress, with a well-researched, engaging account of the Republicans and pro-Union Democrats’ strategy to preserve the Union. Their opponents—New York Senator Charles Seward, Lincoln’s presidential rival; Ohio Republican Representative and former Whig Senator and secretary of the Treasury, Thomas Corwin; and Charles Francis Adams—receive equal treatment.

Unlike the actual 13th Amendment, which returned the nation to the Declaration of Independence’s understanding of natural rights, its predecessor would have legitimized the founding’s moral compromise of slavery, making that stain harder to remove by repudiating the Declaration. In his August 22, 1862 letter to Horace Greeley, Lincoln argued that “My paramount object in this struggle is to save the Union, and is not either to save or to destroy slavery.” Lincoln’s civil war statesmanship revolved around the meaning of “saving” the Union, the content of that saving deepening throughout the war. Lincoln led the nation from First Inaugural necessity to the Second Inaugural fulfillment, from the salvation of the country to the salvation of its soul.