Major-General GEORGE B. MCCLELLAN:
The President, having considered the plan of operations agreed upon by yourself and the commanders of army corps, makes no objection to the same, but gives the following directions as to its execution:
1. Leave such force at Manassas Junction as shall make it entirely certain that the enemy shall not repossess himself of that position and line of communication.
2. Leave Washington entirely secure.
3.Move the remainder of the force down the Potomac, choosing a new base at Fortress Monroe, or anywhere between here and there, or, at all events, move such remainder of the army at once in pursuit of the enemy by some route.
EDWIN M. STANTON,
Secretary of War
Abraham Lincoln, Executive Order Online by Gerhard Peters and John T. Woolley, The American Presidency Project https://www.presidency.ucsb.edu/node/202539