The Bible tells us that, about 1,300 B.C., Joshua, the successor to Moses, sent spies into Canaan to “view the land” prior to the Israelites’ attack on the city of Jericho (Joshua 2.1). Previously, Joshua had served as a spy for Moses.
“Spies are a most important element in war, because upon them depends an army’s ability to move.” As James Clavell points out in “The Art of War,” the Chinese general Sun Tzu wrote those words in the 5th century B.C. in explanation for his success in defending his ruling sovereign against invading enemies.
In more recent times, Thomas B. Allen wrote in “George Washington, Spymaster” that, during the Revolutionary War, General Washington believed, “There is nothing more necessary than good intelligence to frustrate a designing enemy, & nothing that requires greater pains to obtain.” Yet, when the Civil War erupted in 1861, neither the Union nor Confederacy had a viable military intelligence capability.
The reason for this was the United States government looked upon spying as a nefarious activity and did not establish a permanent intelligence organization once it had gained independence from Great Britain. As a result, individual armies on both sides during the Civil War scrambled to establish an information-gathering apparatus in order to learn about the disposition, strength and intentions of enemy forces they were confronting.
Because of its mobility, cavalry became the primary means for observing the enemy in the field. Cavalry commanders designated scouts to go into the countryside where the enemy was maneuvering and bring back information for incorporation into operational plans.
However, by 1863, two years into the war, Union Maj. Gen. Joseph Hooker recognized the need for a more comprehensive military intelligence capability. He assigned Col. George H. Sharpe the responsibility to organize an intelligence staff that would provide Hooker with detailed and reliable data about the enemy forces he was confronting, the Army of Northern Virginia under Gen. Robert E. Lee.
Hooker chose wisely, because Sharpe, who had been a lawyer in civilian life before he joined the army to help put down the Southern rebellion, brought to the job experience and skills in evaluating information for accuracy and reliability. Sharpe formed a unit consisting of some 20 men that he labeled the Bureau of Military Information.
Sharpe devised a methodology for integrating information collected by a variety of sources in order to prepare comprehensive reports for his commander. Those sources included cavalry, signal corps, military telegraph, special operations units, topographical engineers and an airborne balloon corps.
The signal corps observed enemy movements from elevated locations and transmitted what they learned by signal flags from outlying stations, sometimes by relay, to the station at command headquarters. The military telegraph units connected various army elements by portable field wire, so that information from the commanding general could be disseminated expeditiously.
Specially-trained sharpshooter regiments served as skirmishers, moving out ahead of the army to “feel” the enemy locations and report back what they learned. Those units also served a counterintelligence role by denying enemy skirmishers close access to the main army.
Topographical engineers operated between the lines or behind enemy lines to sketch the terrain and its important features, such as roads, bridges, streams, etc., and prepared maps for operational purposes. The balloon corps observed the enemy from tethered positions at considerable altitude and transmitted that information by telegraph wire from the balloon gondola to the ground.
It was the job of the BMI to analyze and synthesize the data arriving from these sources, and to prepare finished product reports for the commanding general. That process was unique in that only the Union Army of the Potomac under Hooker had developed this capability.
Sharpe gained additional information about the enemy by interrogating prisoners, enemy deserters, refugees and escaped slaves, all of whom had recent contact with the enemy and were able to provide valuable current information.
Sharpe used incentives for those sources to reveal what they knew about the enemy’s plans and objectives. They included better treatment while in captivity, release to work in the North on farms and in factories, an opportunity to join the Union army and serve out West away from the war zone and releasing the men to return to their homes if they lived in territory occupied by Union forces.
Sharpe was a pioneer in the intelligence field. He established a precedent during the 19th century for all-source information gathering that would be mimicked by the United States intelligence community in modern times.
Thomas J. Ryan is the author of “Spies, Scouts & Secrets in the Gettysburg Campaign” and “Essays on Delaware during the Civil War” (signed copies available at Bethany Beach Books). Contact him at email@example.com or visit his website at www.tomryan-civilwar.com.