This unexpected backward movement upon their part
deprived the Urbana route, which McClellan had hitherto so strenuously
advocated, of its chief strategic advantages, and therefore reopened the
old question which had been discussed between him and Mr. Lincoln. To
the civilian mind a movement after the retreating enemy along the direct
line to Richmond, now more than ever before, seemed the natural scheme.
But to this McClellan still remained unalterably opposed. In the letter
of February 3 he had said: "The worst coming to the worst, we can take
Fort Monroe as a base and operate with complete security, although with
less celerity and brilliancy of results, up the Peninsula." This route,
low as he had then placed it in order of desirability, he now adopted as
the best resource, or rather as the only measure; and his judgment was
ratified upon March 13 by unanimous approval on the part of his four
corps commanders. They however made their approval dependent upon
conditions, among which were: that, before beginning the advance along
this line, the new rebel ram Merrimac (or Virginia), just finished at
Norfolk on the James River, should be neutralized, and that a naval
auxiliary force should silence, or be ready to aid in silencing, the
rebel batteries on the York River. In fact, and very unfortunately, the
former of these conditions was not fulfilled until the time of its
usefulness for this specific purpose was over, and the latter condition
was entirely neglected. It was also distinctly stipulated that "the
force to be left to cover Washington shall be such as to give an entire
feeling of security for its safety from menace." Keyes, Heintzelman and
McDowell conceived "that, with the forts on the right bank of the
Potomac fully garrisoned, and those on the left bank occupied, a
covering force, in front of the Virginia line, of 25,000 men would
suffice." Sumner said: "A total of 40,000 for the defense of the city
would suffice."[4] On the same day Stanton informed McClellan that the
President "made no objection" to this plan, but directed that a
sufficient force should be left to hold Manassas Junction and to make
Washington "entirely secure." The closing sentence was: "At all events,
move ... at once in pursuit of the enemy by some route." Thus at last
two important facts were established: that the route up the Peninsula
should be tried; and that the patience of the administration was
exhausted.

Though the enemy upon hi