No. Slavery was not the cause of secession. It was merely the legal pretext. Lincoln did orchestrate the writing and passage of the Corwin Amendment. Abolitionists were a tiny despised minority. the Morrill Tariff was the primary cause of secession.
Then on February 18, 1861, Jefferson Davis was inaugurated as president of the Confederacy during a ceremony in Montgomery, Alabama.
The Morrill Tariff did not pass Congress until March 2, 1861, after the withdrawal of opposing Southern Senators due to secession.
Call me deluded, but in my history books, events do not happen before causes appear.