The real reason for Mr. Johnson's withdrawal was Vietnam. It was an involvement he had questioned as a Senator and about which he brooded as President. There were too many casualties. In addition, Mr. Johnson had begun to doubt our ability to prosecute the war to any clear-cut victory.
So many men were ready to enlist because of what the war was about. In the South, men wanted to enlist so they could keep their slaves to do their work for them. In the North, men were ready to enlist because they thought slavery was wrong, as it was.
It would let them starve so they would either surrender or all die out and destroy whats left of Germany. ☺