That gave the Confederacy enough size and resources to make the Civil War a long and bloody contest. Formally, for the first phase of the Civil War, the Union's war objective was not the elimination of slavery but preservation of the Union. At least initially, the South preferred to talk mostly of the South's right to be independent. Yet a close reading of the articles of secession passed by the state legislatures who joined the Confederacy show that the preservation of slavery -- often referred to gingerly as the South's "peculiar institution" -- was the reason why the South wanted independence.
Looked on dispassionately, one notices the haphazard way in which the Civil War began. There was no ultimatum by the North over slavery, simply the election of the antislavery Lincoln as President. After Lincoln was elected, he attempted to soothe Southern anxieties over slavery. Only after Gettysburg in July of 1863 did Lincoln issue the Emancipation Proclamation effectively ending slavery. Even then, it was framed as a war measure instead of a full-on abolition. The formal and complete abolition of slavery was not written into the Constitution until the 14th Amendment was ratified in 1868 -- well after the end of the Civil War.
Are people including the effects of the cotton gin and mechanization on plantation life?
“Only after Gettysburg in July of 1863 did Lincoln issue the Emancipation Proclamation effectively ending slavery.”
Not quite the case. The Emancipation Proclamation was issued after the Battle of Antietam which occurred in September 1862. The Proclamation took effect on January 1, 1863. The Battle of Gettysburg didn’t take place until July, 1-3 1863.