Answer:
The main difference between the motivation of the Founding Fathers at the time of starting the Revolutionary War and the motivation of the Secessionists to create the Confederation (which led to the Civil War) was that, in the case of the Founding Fathers, it was of the defense of a series of liberal values that implied the construction of a nation based on democracy and equality; while in the case of the Secessionists it was about the opposite, that is, to guarantee an inequality between whites and blacks, and subject the latter to a total lack of freedom through the legality of slavery.