In brief, by concentrating all his widely scattered forces, Jackson could bring to bear upon his problem no more than 17,000 men at the very most, while he stood beleaguered by no less than 34,000, under generals who already held the greater part of the valley and seemed easily able to occupy the rest of it, including Staunton and the chief railroad lines, at will.
When Jackson definitely learned that he could have no other help than that of Ewell and Edward Johnson, he boldly planned to concentrate his 17,000 men and with them make war upon his 34,000 adversaries. His hope lay in secrecy and celerity of operation. His plan was to bring the three widely separated parts of his army together without the enemy's knowledge, and to hurl the whole like a thunderbolt against one after another of his enemy's divisions.
The largest of those divisions,—that under Banks's personal command at Harrisonburg—outnumbered Jackson's total force by all of 2,000 men, while the other two divisions were nearly enough equal to his own to make an assault upon either of them perilous. Moreover the geographical problem was such that Jackson could at no point bring all his inferior force to bear at once. He must always keep a considerable part of it detached and out of action, lest his adversary seize upon a position of commanding importance.
Nevertheless, this truly Napoleonic commander planned a campaign in which, with his 17,000 men, he should defend Staunton and destroy in detail his adversary's double numbers.
Thus began that campaign whose strategy has been called by a historian "massive thimble-rigging," because its success depended upon Jackson's ability to conceal his movements and make sudden appearances in quite unexpected places.
The season was highly unfavorable for rapid marchings. The roads were quagmires and the fields on either side of the highways were morasses. Sometimes it was impossible, even by the most heroic endeavors, to move the guns more than five miles in a day. Rain and mud offered obstacles immeasurably more obstinate than hostile battalions, but in spite of all, Jackson persisted.
His first purpose was to unite the force under his own immediate command at Swift Run Gap, with the troops under Edward Johnson at West View, west of Staunton and forty miles or more away. He began by ordering Ewell, with his 8,000 men, to cross the Blue Ridge from the east, and occupy Swift Run Gap. While Ewell was executing this movement Jackson, with his 6,000 men and with the purpose of deceiving his enemy, moved northward down the valley, turned eastward, crossed the mountains to their eastern side, and then by a circuitous route made his way back again westward across the mountains to join Edward Johnson west of Staunton. His purpose in all this was to convince his enemy that he was abandoning and evacuating the Valley and marching to join the Confederate forces defending Richmond.
He accomplished that deception perfectly, and so secretly was his return to the Valley conducted that the pushing of his column into Staunton astonished the Confederates there quite as much as it would have astonished the Federals if they had known of it, as they did not.
Ewell, had in the meanwhile, crossed the Blue Ridge and occupied the position left by Jackson in the Elk Run valley. Unfortunately for Jackson, that position must be held at all hazards, and so it was impossible for him, for the present at least, to add Ewell's 8,000 men to the meager forces with which he intended to assail the Federals farther west.
Thus Jackson's campaign was begun with only Edward Johnson's force, numbering a scant 3,000 men, and his own battalions, amounting to 6,000, or somewhat less. He had in all a force of about 8,500 men or perhaps a trifle more, with which to deal with Milroy and Schenck, who had 6,000 men at McDowell, the much larger forces of Fremont advancing from the west, and such reinforcements as Banks might choose to send to them from his army of 19,000 men at Harrisonburg.