The Cornerstone Speech as delivered by Confederate Vice President Alexander Hamilton Stephens on March 21st 1861 in Savannah, Georgia. It explained the differences between the constitutions of the United State and the Confederate Republic. In the speech Stephens defended slavery and explained the need for the Civil War. The speech outlined the Confederate constitution including the elimination of tariffs, and the rights of the states above all. The date of the speech was just a few weeks after several southern states seceded and only three week after Abraham Lincoln was inaugurated.
If you would like to read the speech Cornerstone Speech is the place.