IX. the Gettysburg campaign. June—July, 1863.
I. Theory of the Confederate invasion.In the minds of that group of able and sagacious men that at Richmond controlled the course of the mighty experiment of war, there had early grown up a theory of military conduct that was undoubtedly the best adapted to the circumstances, and, indeed, is the only theory on which a defensive war can be maintained with any hope of success. It is now generally conceded that a Power that either voluntarily or by compulsion allows itself to be reduced to a purely defensive attitude is certain to be compelled, sooner or later, to succumb. On the other hand, military history affords many memorable illustrations of the marvellous results that may be accomplished by nations that, forced to the defensive by the superiority of the assailant, are yet able at the opportune moment to assume the offensive, and inflict blows as well as receive them. It was by acting on this principle that Frederick the Great, in that everlasting model of a defensive campaign, the Seven Years War, was able to make head against the seemingly overwhelming combination brought against him; and that Napoleon, in 1814, in that other bright exemplar of the defence of a country by boldly taking the offensive, was able to confront the invading Allies, and at length make them pay so dearly for the capture of his capital.  Such was the principle of action early adopted by the Confederate leaders; and the course of this narrative has already set forth the bold and successful manner in which it was more than once carried out. It was in accordance with this policy that General Johnston, after falling back from Yorktown to the front of Richmond, turned upon McClellan astride the Chickahominy, and dealt him a blow which but for accidental circumstances should have terminated the campaign—a result that, indeed, was accomplished, when Lee, continuing the conception of Johnston, seized the initiative and hurled the Union army back to the James River. And it was in following out the same line of action that he was able, by threatening the flanks and rear of Pope, to drive back that general to the fortifications of Washington, and transfer the theatre of war to the trans-Potomac region. It seemed that an opportunity for a new and bolder offensive than had yet been attempted now presented itself. Twice the Army of the Potomac had crossed the Rappahannock, and on each occasion it had been driven back in disaster. Fredericksburg and Chancellorsville had raised the morale of Lee's army to the highest pitch. While the experience of these battles had inspirited the Southern troops, it had given General Lee himself a sense of confidence and power he had not before felt. And now to this fact of the moral condition of the Confederate army, so favorable to bold enterprises, was added another incentive, in its condition of material strength. The diminution of Hooker's force by the extensive out-mustering of short-term troops1 was well known;  and to this relative increase of Lee's army was now added a positive increase by a large force of conscripts, and a more important re-enforcement by the two divisions of Longstreet's corps, which, having been operating south of James River at the time of the battle of Chancellorsville, were immediately thereafter recalled to take part in the meditated movement. If Hooker's force of infantry was at this time reduced, as he de dares, to an effective of eighty thousand men,2 there was now less disproportion between the two armies than generally obtained, for at the end of May, Lee's force had reached an aggregate of sixty-eight thousand infantry and a considerable body of cavalry.3 The Confederate army had, moreover, been lately mobilized and increased in efficiency by its reorganization into three corps d'armee, under Generals Longstreet, Hill, and Ewell—three able, energetic, and trusted lieutenants. In respect of transportation, equipment, and clothing, though not in respect of supplies, the Southern force in Virginia was in better condition than at any previous time. And if its commissariat was deficient, the rich granaries of the North lay open—the inviting spoils of a successful blow.4  Thus prompted, the Confederate leaders resolved upon a movement that should not only have the effect of causing the Army of the Potomac to loose its hold upon the Rappahannock, but should initiate a campaign of invasion on the soil of the loyal States. And it is proper to point out here that in coming to this determination, those who controlled the warcouncils at Richmond would seem to have been influenced rather by the excited condition of the army and the South, than by a just appreciation of their proper defensive policy. This not only did not exclude, but it invited the seizing of favorable opportunities to throw back the Army of the Potomac from its aggressive advances into Virginia, and, if possible, force it across the Potomac. But to convert these offensive returns into out-and-out invasion was to overleap their true policy and enter upon an' enterprise uncertain, perilous, and costly. The experience of the Maryland campaign of the previous year might already have made this manifest; and hence it would appear that the Richmond leaders, in resolving to push the aggression into Pennsylvania, took counsel not so much from prudence as from the clamors of the Hotspurs of the South, who, fretting at the defensive attitude held by Lee during the past twelve months, now burned to see the theatre of war transferred to Northern soil.5 The close of May found the army ready to launch on this seductive but fatal adventure.