But in that Lee, by delaying the advance of his enemy a whole day, thereby gained time to bring together his own scattered forces, it was strategically a victory, though a costly one, for him. But then again it might be argued that if Lee could have kept the four thousand good troops that McClellan deprived him of at South Mountain, it might have fared better with him in the struggle at Antietam three days later. When Lee retired his left wing from Turner's Gap, he withdrew across the Antietam, and took up a position on high ground between that stream and the village of Sharpsburg. His right, under McLaws, after detaining Franklin till Harper's Ferry was surrendered, crossed the Potomac at that place, recrossed it at Shepherdstown, and came promptly into position. Lee now had his army together and strongly posted. But it had been so reduced by losses in battle and straggling, that it numbered but little over forty thousand combatants. The effect upon the army itself of invading a rich country with troops so poorly supplied had probably not been anticipated. Lee complained bitterly that his army was "ruined by straggling," and General Hill wrote in his report: "Had all our stragglers been up, McClellan's army would have been completely crushed or annihilated. Thousands of thievish poltroons had kept away from sheer cowardice." General Hill, in his anger, probably overestimates the effect; for McClellan had somewhat over seventy thousand men, and though he used but little more than half of them in his attacks, there is no reason to suppose he would not have used them all in a defence. The men that Lee did have, however, were those exclusively that had been able to stand the hard marching and resist the temptation to straggle, and were consequently the flower of his army; and they now awaited, in a chosen position, a battle that they knew would be decisive of the campaign, if not of the war.