Just some points for clarification.
Please read Lincolns first innaugrel speech.
The South (South Carolina) fired on Fort Sumter. As a result of this, Lincoln called for the raising of 95,000 troops for 3 months service. Their battle cry was "preserve the Union".
Once Lincoln issued his Emancipation Proclamation, many in the North were furious, because the focus of the war changed to freeing the slaves, not about preserving the Union. Shortly after, conscription began in the North, as the it was then harder to "Rally 'round the Flag" when the cause was no longer one you could die for.
Robert E. Lee was, in my mind, a great general. He maintained the ANV through years of inept and lackadaisical supply. But, he failed to realize there was more war than just that in Virginia. Gettysburg was a great battle, but at the same time, the siege of Vicksburg was ended. A solid argument can be made that the South lost the war at Shiloh, by not pressing Grant. There's an old saying, "The South never smiled after Shiloh".
Also in my opinion, Longstreet bore the brunt of the failure at Gettysburg because he alone of the top CSA Generals at the battle, was not a Virginian.
To get a good grasp of the situation as it actually was, start reading biographies from the period. Not just the popular ones, try them all. Some will impress you, others will make your blood boil. But you'll come away with what actually happened, ( if you pair them with official records and period maps). Our accounts of historical periods get distorted with every new book published.
