Shortly before the surrender at Appomattox, Jefferson Davis and various of Lee's generals wanted him to break up the Army of Northern Virginia and head for the hillls to continue resistance through guerrilla warfare. To Lee's everlasting credit he did not/would not do this. If he had done so...... By that stage of the war, the Federal Army would have extirpated the south. If you think that Sherman's march to the sea or the burning time in the Shennandoah Valley were bad, think of what would have happened. The guerrillas and their supporters would no longer have been covered by General Order Number 100, 24 April 1863 (the Lieber Code), in that a Confederate government and command structure would no longer have existed.
The Lieber Code was the first detailed, written articulation of the law of land warfare. In many respects it formed the basis of the Hague Conventions of 1899 and 1909 and the four Geneva Conventions of 1949. The Lieber Code first articulated, for example, the principle that in order to be considered soldiers men had to have an organized command structure, had to wear uniforms or a "mark" recognisable at a distance, carry their arms openly, and obey the laws of war themselves. The force that Davis proposed could not have done this, and consequently would have been literaly outside the law of war. The consequences for the southern population are obvious.
Lincoln transmitted a copy of GO 100 to Jefferson Davis shortly after it was issued, and advised him that the Federal Army expected that the Confederate Army would abide by its rules. As someone interested in the Civil War, I would suggest that you read it. If you are currently a soldier, it still has an impact on the expectations of your lawful behavior in war.
Regards,
Don Dixon