Lee's balancing of the ponderables on the military scales was accurate. He couldn't realize, and few even in Washington could see, that an imponderable was tipping the beam. That imponderable was the influence of President Lincoln. ... References to Lincoln in Lee's correspondence and conversation were rare. He was much more interested in the Federal field-commanders than in the commander-in-chief. After the late winter of 1863-64, had Lee known all the facts, he'd have given as much care to the study of the mind of the Federal President as to the analysis of the strategical methods of his immediate adversaries. For that remarkable man, who had never wavered in his purpose to preserve the Union, had now mustered all his resources of patience and of determination. Those who had sought cunningly to lead him, slowly found that he was leading them. His unconquerable spirit, in some mysterious manner, was being infused into the North as spring approached.