Texas after that state seceded from the Union. American Civil War After the start of the Civil War, Porter became chief of staff and assistant adjutant general for the Department of Pennsylvania, but he was soon promoted to colonel of the 15th Infantry on May 14, 1861. General John A. Logan, Porter's later political nemesis, would accuse Porter of helping persuade his commander Robert Patterson to let Joseph E. Johnston's force escape out of the Shenandoah Valley and reinforce P. G. T. Beauregard, thus turning the tide at the First Battle of Bull Run. In August, Porter was promoted to brigadier general of volunteers, backdated to May 17 so he would be senior enough to receive divisional command in the Army of the Potomac, newly formed under Maj. Gen. George B. McClellan. Soon Porter became a trusted adviser and loyal friend to McClellan, but his association with the soon-to-be-controversial commanding general would prove to be disastrous for Porter's military career. Porter led his division at the beginning of the Peninsula Campaign, seeing action at the Siege of Yorktown. McClellan created two provisional corps and Porter was assigned to command the V Corps. During the Seven Days Battles, and particularly at the Battle of Gaines' Mill, he displayed a talent for defensive fighting. At the Battle of Malvern Hill, Porter also played a leading role. Inadvertent balloon ride In addition, Porter had a memorable experience when he decided to make aerial observations in a hot air balloon without the assigned expert to handle the craft, Professor Thaddeus Lowe. When he ascended with only one securing line, the balloon subsequently broke loose and General Porter found himself drifting west over enemy lines in danger of being captured or killed. Fortunately, the combination of a favorable wind change and himself adjusting the gas values allowed Porter to return to the Union lines and land safely. Although it was an embarrassing accident, General Porter was able to perform his observations of enemy defences as intended and recorded his findings, although the balloon program was disbanded a year later. For his successful performance on the peninsula, he was promoted to major general of volunteers on July 4, 1862. Second Bull Run Porter's corps was sent to reinforce Maj. Gen. John Pope in the Northern Virginia Campaign, a reassignment that he openly challenged and complained about, criticizing Pope personally. During the Second Battle of Bull Run,