Lincoln’s remonstrances, however, had no great weight with McClellan.  The general paid little heed to the political situation.  His chief argument in favour of the expedition by sea had been the strength of the fortifications at Manassas.  Johnston’s retreat on March 9 removed this obstacle from his path; but although he immediately marched his whole army in pursuit, he still remained constant to his favourite idea.  The road to Richmond from Washington involved a march of one hundred miles, over a difficult country, with a single railway as the line of supply.  The route from the coast, although little shorter, was certainly easier.  Fortress Monroe had remained in Federal hands.  Landing under the shelter of its guns, he would push forward, aided by the navy, to West Point, the terminus of the York River Railroad, within thirty miles of Richmond, transporting his supplies by water.  Washington, with the garrison he would leave behind, would in his opinion be quite secure.  The Confederates would be compelled to concentrate for the defence of their capital, and a resolute endeavour on their part to cross the Potomac was forbidden by every rule of strategy.  Had not Johnston, in his retreat, burnt the railway bridges?  Could there be a surer indication that he had no intention of returning?

Such was McClellan’s reasoning, and, putting politics aside, it was perfectly sound.  Lincoln reluctantly yielded, and on March 17 the Army of the Potomac, withdrawing by successive divisions from Centreville to Alexandria, began its embarkation for the Peninsula, the region, in McClellan’s words, “of sandy roads and short land transportation."* (* O.R. volume 11 part 3 page 7.) The vessels assembled at Alexandria could only carry 10,000 men, thus involving at least fifteen voyages to and fro.  Yet the Commander-in-Chief was full of confidence.  To the little force in the Shenandoah Valley, flying southward before Shields, he gave no thought.  It would have been nothing short of miraculous had he even suspected that 4500 men, under a professor of the higher mathematics, might bring to naught the operations of his gigantic host.  Jackson was not even to be followed.  Of Banks’ three divisions, Shields’, Sedgwick’s, and Williams’, that of Shields alone was considered sufficient to protect Harper’s Ferry, the Baltimore and Ohio Railway, and the Chesapeake Canal.* (* Ibid page 11.) Banks, with the remainder of his army, was to move at once to Manassas, and cover the approaches to Washington east of the Blue Ridge.  Sedgwick had already been detached to join McClellan; and on March 20 Williams’ division began its march towards Manassas, while Shields fell back on Winchester.

March 21.

(Map.  Situation, night of march 21, 1862.  Showing:  West:  McDowell,
North:  Baltimore, South:  Yorktown and East:  Urbanna.)