But, the "lost Cause" of the Confederacy was not just an empire, a group of states gathered together. The Confedracy's "Lost Cause" was an Ideal. It fact it was a dangerous ideal to those who wish to have power, when it is in the hands of free men, It was Liberty.
That is a strange word Liberty. Most people think "Liberty" means "Freedom", but it doesn't. "Freedom" is a conditions which is allowed by other men as to what you are allowed to do. Such as you have the Freedom of Speech and the Freedom of Religion. Freedoms can be enacted or legislated away. But "Liberty" is a different. "Liberty" is the condition by which you can establish your own "Freedoms".
It was the desire for Liberty to govern themselves that drove the American Colonies to seek their independence from the Bristish Empire, And it was same desire for Liberty for the Southern States who sought their independence from the control of the United States Empire.