General Patrick's Progress: Intelligence and Security in the Army of the Potomac

GENERAL PATRICK'S PROGRESS: Intelligence and Security in the Army of the Potomac David S. Sparks An astonishing number of people, civilian as well as military, participated in the intelligence and security operations of the Army of the Potomac.1 Private detectives, secret service operatives, amateur spies, scouts, guides, cavalrymen, and the provost marshals all took some part in the task of protecting the security of the army and in the attempt to ferret out information about enemy numbers, positions, and intentions. At first very little coordination existed among the many individuals and organizations engaged in the work. As a result, the record is filled with instances of vague directives, conflicting authorities, and scrambled organizations. Not only did the right hand frequently not know what the left hand was doing, it was scarcely aware of its existence . In the course of the war, however, organizations and procedures developed, and well before Appomattox the Army of the Potomac possessed a relatively sophisticated and surprisingly efficient intelligence service. On the other hand, müitary security proved somewhat less effective. The disparity in the effectiveness of intelligence and security operations is traceable to several facts. The most important of these was something common to all civil wars—namely that simdarities of language , social habits, and appearances, as well as familiarity with local terrain, made it easy for intelligence agents on both sides to obtain accurate information, while making it almost impossible for those charged with security to halt the flow of either persons or information to the enemy. And, of course, the Army of the Potomac was additionally handicapped by the fact that for most of its existence it was operating in Southern territory where every civilian was a potential spy, guide, or scout for the Confederacy. This disadvantage was partly over1 No established intelligence service or provost marshal organization existed at the outbreak of hostilities. For a brief discussion of the Civil War origins of the latter see Wilton P. Moore, "Union Provost Marshals in the Eastern Theater," Military Affairs, XXVI (1962), 120-126. 371 372civil war history come by the readiness of Negro refugees, "contrabands" in the parlance of the day, to supply any information they possessed. Finding high-placed persons, willing to serve the Union cause, remained difficult , however. The attempt to protect the security of the army was also impeded by policies emanating from the Lincoln administration in Washington. Eager to win and maintain the support of the people, in the South as well as in the North, the administration adopted generous pass and trade regulations which served to facilitate the flow of both persons and information out of Union lines as well as into them. Throughout the war, the Lincoln government sought to restore loyalty, not punish treason, and was unwilling to adopt measures sufficientiy stringent for good military security. The initial security efforts of the Army of the Potomac, such as they were, grew out of the need to maintain law and order in Washington when thousands of raw troops arrived in the spring and early summer of 1861. A provost guard was soon organized and given the task of patrolling the streets to curb the excesses brought on by high, low, or alcoholic spirits. Brigadier General Irvin McDowell resorted to similar expedients to curb the looting of Virginia householders along the route of his ill-starred advance to Bull Run in mid-July. He ordered that one officer and ten men from each regiment be detailed to protect the property of Virginians in the path of his troops.2 When Major General George B. McClellan assumed command of McDowell's defeated forces he promptly put police and security matters on a more regular basis. He created a provost marshal organization and appointed Colonel Andrew Porter, of the 16th U.S. Infantry Regiment, as his provost marshal general.3 Porter's initial task was simply to maintain order and help reestablish discipline among the dejected citizen-soldiers McClellan was trying to mold into an army. He was given no direct responsibdity for either security or intelligence matters. In February, 1862, Porter became provost marshal general of the Army of the Potomac with a greatly expanded provost organization...