 The immediate problem with McClellan 's war strategy was that he was convinced the Confederates were ready to attack him with overwhelming numbers . On August 8 , believing that the Confederacy had over 100 @,@ 000 troops facing him ( in contrast to the 35 @,@ 000 they actually deployed at Bull Run a few weeks earlier ) , he declared a state of emergency in the capital . By August 19 , he estimated 150 @,@ 000 rebel soldiers on his front . McClellan 's subsequent campaigns were strongly influenced by the overblown enemy strength estimates of his secret service chief , detective Allan Pinkerton , but in August 1861 , these estimates were entirely McClellan 's own . The result was a level of extreme caution that sapped the initiative of McClellan 's army and dismayed the government . Historian and biographer Stephen W. Sears observed that McClellan 's actions would have been " essentially sound " for a commander who was as outnumbered as McClellan thought he was , but McClellan in fact rarely had less than a two @-@ to @-@ one advantage over the armies that opposed him in 1861 and 1862 . That fall , for example , Confederate forces ranged from 35 @,@ 000 to 60 @,@ 000 , whereas the Army of the Potomac in September numbered 122 @,@ 000 men ; in early December 170 @,@ 000 ; by year end , 192 @,@ 000 . 
