...itting Lee's movement can prevent Meade from reinforcing Rosecrans and drive the former across the Potomac, Lee cannot prevent Rosecrans from being reinforced by about 40,000 or 50,000 men from Ohio, Kentucky , Indiana, Missouri, and the Mississippi Valley, in about one month's time; hence, admitting that Rosecrans has now about your own supposed effective force—say 60,000 men of all arms—he wi...