But there were not just two positions that one could hold about slavery. Nearly all of the American politicians in the first half of the 20th century took a position somewhere in between William Lloyd Garrison (who felt that slavery was an indisputable moral evil that should be eradicated from the face of the earth) and John C. Calhoun (who wrote that slavery was a positive moral good for blacks and whites alike and should be required in every state).
Emancipation was not even on the table in 1858. The major question at issue was how to handle slavery in the new territories that were then coming into the union. Douglas had hitched his star to “popular sovereignty,” or the position that each territory should decide for itself whether or not to allow slavery. Lincoln argued that while the federal government should not interfere with slavery where it existed, it should not allow expansion into any new territories.
These two positions dominated the Lincoln-Douglas debates, which were conducted in a format that we have never seen since. One candidate gave a 30-minute introduction, followed by a 90-minute speech by the other candidate, and a 60-minute rebuttal by the first. They were three-hour debates, and they required a lot more than sound bites.
But for all of that, Lincoln and Douglas spent most of the first four debates talking past each other. They both ignored the nuances of the other’s position and spent their time beating up the kinds of straw-man arguments that result from trying to force an opponent to defend the most extreme characterization of the position that they hold.
In the fifth debate, however, Lincoln changed his approach—and the course of American history forever—when he simply clarified the real terms of the argument:
"I suppose that the real difference between Judge Douglas and his friends, and the Republicans on the contrary, is, that the Judge is not in favor of making any difference between slavery and liberty-that he is in favor of eradicating, of pressing out of view, the questions of preference in this country for free or slave institutions; and consequently every sentiment he utters discards the idea that there is any wrong in slavery. Every thing that emanates from him or his coadjutors in their course of policy, carefully excludes the thought that there is any thing wrong in slavery. All their arguments, if you will consider them, will be seen to exclude the thought that there is any thing whatever wrong in slavery."
This was a very simple shift in a debating tactic, but an enormous shift in emphasis. Douglas did not disagree. He couldn’t. Even the suggestion that he felt that slavery was morally problematic would have cost Douglas any chance at the Democratic presidential nomination in 1860.
However, from this point on, rather than arguing about possible policies, or the intentions of the Founding Fathers, or the various implications of the Supreme Court’s Dred Scott decision, or any of the other things that they spent most of the first four debates discussing, they spent much of their time in the last three debates talking about the most important moral question of the century: Is slavery wrong?
Lincoln lost the election, but he created a sense of moral and intellectual clarity that guided him, and the Republican Party, through the 1860 election and the Civil War.
And this is the power of clarifying what an argument is really about. Very few political arguments today reach what rhetoricians call the “point of stasis,” where the parties fully agree about where they disagree. When an argument has not reached a point of stasis, participants almost always push past each other and argue about glaring generalities, ridiculous extremes, and culturally prominent straw-men. When an argument reaches stasis, however, political arguments become capable of revealing positions, changing minds, and doing the hard work of democracy.
And this is why, in my opinion, the most important thing that Abraham Lincoln did in 1858 was to clarify the terms of the most important argument of the nineteenth century.