Once the security force makes enemy contact, it does not break contact unless the main force commander specifically directs it. However, the individual security asset that first makes contact does not have to maintain that contact, if the entire security force maintains contact with the enemy. The security force commander ensures that subordinate security assets hand off contact with the enemy from one security asset to another in this case. The security force must continuously collect information on the enemy's activities to assist the main body in determining potential and actual enemy COAs and to prevent the enemy from surprising the main body. This requires the security force to maintain continuous visual contact, to be able to use direct and indirect fires, and to freely maneuver, which requires the security force have depth in space and time.
On the morning of 1 July 1862 a Confederate force of nearly 5,000 soldiers led by Brigadier General John R. Chalmers moved toward the Union supply depot at Corinth, Mississippi. Their path led them through Booneville, Mississippi. This town was held by a blocking force of Union cavalry commanded by Colonel Philip Sheridan that included the 2d Michigan and 2d Iowa Cavalry Regiments. He deployed a picket line forward of his main position to provide early warning of hostile forces.
Chalmers lead combat units encountered Sheridan’s picket line, triggering a brief exchange of gunfire. This contact alerted Sheridan to the Confederate presence and ensured his main force sufficient time to deploy for battle. The Union pickets conducted a fighting withdrawal, seeking to slow the Confederate advance without becoming decisively engaged.
Several roads led into and around Booneville. The Union picket line initially covered the most likely avenues of approach for the Confederates. However, as the picket line conducted its fighting withdrawal, one of the officers supervising its actions, Captain Russell Alexander, learned of additional hostile forces moving along other roads, threatening to envelop Sheridan’s main position. He immediately dispatched messengers to Sheridan, alerting his commander to the evolving tactical situation and outlining Confederate dispositions and actions. This information enabled Sheridan to alter his main battle positions to block Charmers’ multi-directional advance.
When the Confederates finally made contact with the main line of Union resistance, they were met with concentrated fire and repulsed. Chalmers made several attempts to overrun Sheridan’s cavalry, but lacking the element of surprise and unable to mount an effective flanking operation, these efforts failed. The early warning and continuous monitoring of Charmers’ actions permitted Sheridan to respond in a timely fashion to emerging threats, thereby reducing each Confederate action to a costly frontal assault. A counterattack by the Union cavalry ensured Confederate defeat, and Chalmers withdrew from the battlefield. Sheridan received promotion to brigadier general for his victory.