Ironically, Abraham Lincoln uttered one of this most famous phrases in defense of allowing the South to keep their institution of slavery. Political debates in the United States over the state of slavery in the Western Territories grew very contentious and were only settled after the Missouri Compromise of 1820 prohibited slavery north of the 36°30′ parallel, except within the proposed state of Missouri. That agreement lasted for three decades, until superseded by the Kansas-Nebraska Act, which allowed the new Midwestern territories above the parallel to decide on slavery by popular vote. That Act was engineered Stephen Douglas, Lincoln’s future opponent for the senatorial seat of Illinois.

On this day, June 16, in 1858 Abraham Lincoln went on the floor of the Hall of Representatives in the state capitol of Springfield to address the Illinois Republican party. Lincoln saw Douglas’ Act as coming dangerously near allowing slavery in the entire nation.

Lincoln said: “‘A house divided against itself cannot stand.’ I believe this government cannot endure permanently half slave and half free. I do not expect the Union to be dissolved; I do not expect the house to fall; but I do expect it will cease to be divided. It will become all one thing, or all the other.”