There was still another fact to be taken into account. Under the mistaken system of short-term enlistments which had been adopted at the North, more than thirty thousand of Hooker's best and most seasoned soldiers were about this time going home. Enlistments at the North had well-nigh ceased under the discouragement of repeated failure, while at the South the conscription law--extended as to age--had resulted in putting pretty nearly every able-bodied white man in all that region into the army. The Army of Northern Virginia was being rapidly swelled in numbers, while the Army of the Potomac was losing many of its best fighting regiments and brigades. The Army of Northern Virginia was flushed by recent and conspicuous victory; the Army of the Potomac was sadly disheartened by a defeat which, in view of its vast superiority in numbers, it could in no wise account for or understand. The Army of Northern Virginia had unbounded confidence in itself and limitless belief in its commander; the Army of the Potomac had no longer any reason to trust itself, and it had utterly lost confidence in the general who had so badly handled it as to subject it to humiliating defeat where it had justly expected to achieve victory quick, certain and decisive. Moved by these considerations Lee at once planned a new invasion of the region north of the Potomac. The enemy confronting him was still superior in numbers, equipment and everything else except spirit and fighting quality and its general. It would not do for Lee to move northward, leaving that army in his rear with full opportunity to destroy his communications, rush upon Richmond and possess the Confederate capital. He must so maneuver as to compel Hooker to fall back upon Washington, precisely as he had done in McClellan's case the year before. Again he successfully played upon the excessive concern felt at the North for the safety of Washington. Having brought Longstreet with two strong divisions from the south side of the James river for his reinforcement, and having brought up every battery and battalion that could be spared from any other position, Lee played again the game he had played against McClellan. While still strongly and securely holding his position at Fredericksburg, he began detaching forces in a way to threaten Washington with an attack in the rear, and to compel Hooker to retire upon the national capital for its defense.