How might Network Science impact the study of the Civil War? One way, which I have been exploring this fall semester, is by analyzing the transmission and reception of information by commanders at key moments in the military events of the war. In particular, the Overland Campaign of May 5 to June 7, 1864, could yield interesting facts once the parameters of information flow have been categorized and organized in a way interpretable by analysis programs such as Gephi and ORA.
“Overland” was perceived at the time as a titanic, horrific event in American history, and it still engenders controversy today. Ulysses S. Grant, commanding the armies of the United States, launched his c. 120,000-strong armies against the c. 60,000-strong army of Robert E. Lee with the aim of destroying the Confederate army as an effective fighting force, or at the very least taking the initiative away from the intimidating rebel general. The opening rounds of the ensuing contest took place in the vicinity of the old Chancellorsville battlefields, at the Wilderness on May 5-6, and at Spotsylvania Court House on May 8-21. In both instances, the Union Army came very close to breaking the Confederates completely, but in the end Lee’s army held while inflicting heavy casualties on its Federal enemy. By the end of the campaign at Cold Harbor in early June, Confederate casualties had surpassed 30,000, and Union casualties were upwards of a shocking 55,000.
Currently I am working on three major historical questions that can be addressed through network analysis. One, not surprisingly, is “who were the central nodes” in the Wilderness and Spotsylvania? By this I mean both who had the greatest amount of information pass through their hands, and who made the key decisions in the battles. Second, what was the commanders’ state of knowledge at any given time during these battles? And third, how did the leadership of the Union’s Army of the Potomac change during the campaign, from the regimental leadership up? A very pertinent fourth question would be how our understanding of the campaign is altered as a result of network analysis.
Establishing the parameters of the data set is fairly challenging, both because the data by its very nature is incomplete and because the data that is chosen depends largely on one’s assumptions going into the project–historical data is not always clearly defined. It also underscores the discussions and debates among historians about how Civil War generals actually received and transmitted information.  By way of brief example, if we examine the opening of the Battle of the Wilderness on May 5, 1864, we are confronted with the immediate question of whether every message from one headquarters to another should count as an edge connecting headquarters’ nodes (which, depending on the question asked, could be a valid approach), or whether every person who handles the message should count as a node. The latter is both more precise and, as Civil War historians would agree, more reflective of the fact that the commander himself could well have been absent from headquarters when crucial messages arrived. It also allows us to notice anomalies, such as the famous instance when George Meade, commanding the Army of the Potomac, bypassed the chain of command, including his own chief of staff, to issue orders directly to a division commander. To complete this kind of network, however, requires a close mining of memoirs and letters as well as official reports, not to mention some deductive reasoning, such as determining if a meeting of commanders had to have taken place even though there is no actual mention of it anywhere. And then there is always the question of how to graph Grant’s relationship with Meade, summarized so succinctly by Meade’s staff officer Theodore Lyman in his letters “General Grant had his station with us (or we with him).” 
The issue of how high casualties affected unit cohesion is a somewhat different and larger issue, and one that will occupy much of my spring term of 2015. In the mean time, we keep moving “by the left flank.”
 Significant studies of command and control in the Civil War include R. Steven Jones’ The Right Hand of Command: Use and Disuse of Personal Staffs in the Civil War (2000); Richard L. DiNardo’s “Longstreet and Jackson Compared: Corps Staff and the Exercise of Command in the Army of Northern Virginia,” in Longstreet: The Man, The Soldier, the Controversy, ed. R. L. DiNardo and A. A. Nofi (1998); and Archer Jones’ Civil War Command and Strategy: The Process of Victory and Defeat (1992).
 COL Theodore Lyman, Meade’s Headquarters 1863-1865, Boston 1922, page 91.