To the South, Bull Run was a Pyrrhic victory.  It relieved Virginia of the pressure of the invasion; it proved to the world that the attitude of the Confederacy was something more than the reckless revolt of a small section; but it led the Government to indulge vain hopes of foreign intervention, and it increased the universal contempt for the military qualities of the Northern soldiers.  The hasty judgment of the people construed a single victory as proof of their superior capacity for war, and the defeat of McDowell’s army was attributed to the cowardice of his volunteers.  The opinion was absolutely erroneous.  Some of the Federal regiments had misbehaved, it is true; seized with sudden panic, to which all raw troops are peculiarly susceptible, they had dispersed before the strong counterstroke of the Confederates.  But the majority had displayed a sterling courage.  There can be little question that the spirit of the infantry depends greatly on the staunchness of the artillery.  A single battery, pushed boldly forward into the front of battle, has often restored the vigour of a wavering line.  Although the losses it inflicts may not be large, the moral effect of its support is undeniable.  So long as the guns hold fast victory seems possible.  But when these useful auxiliaries are driven back or captured a general depression becomes inevitable.  The retreat of the artillery strikes a chill into the fighting line which is ominous of defeat, and it is a wise regulation that compels the batteries, even when their ammunition is exhausted, to stand their ground.  The Federal infantry at Bull Run had seen their artillery overwhelmed, the teams destroyed, the gunners shot down, and the enemy’s riflemen swarming amongst the abandoned pieces.  But so vigorous had been their efforts to restore the battle, that the front of the defence had been with difficulty maintained; the guns, though they were eventually lost, had been retaken; and without the assistance of their artillery, but exposed to the fire, at closest range, of more than one battery, the Northern regiments had boldly pushed forward across the Henry Hill.  The Confederates, during the greater part of the battle, were certainly outnumbered; but at the close they were the stronger, and the piecemeal attacks of the Federals neutralised the superiority which the invading army originally possessed.

McDowell appears to have employed 18,000 troops in the attack; Johnston and Beauregard about the same number.* (* For the strength of divisions and brigades, see the Note at the end of the chapter.)

A comparison of the relative strength of the two armies, considering that raw troops have a decided advantage on the defensive, detracts, to a certain degree, from the credit of the victory; and it will hardly be questioned that had the tactics of the Federals been better the victory would have been theirs.  The turning movement by Sudley Springs was a skilful manoeuvre, and completely surprised both Johnston and Beauregard.  It was undoubtedly risky, but it was far less dangerous than a direct attack on the strong position along Bull Run.