In Louisiana, Ignacio Marquez had convinced Governor Randolph Boucher that the greatest threat to his government and to the Federal cause was the forces on the Mississippi commanded by James Longstreet. There were three separate commands available that might be used against him: the
La Patria Division, commanded by Major General Emilano Garcia, The Louisiana Rifles, commanded by Brevet General R.E. Post and the Harrisonburg Brigade under the able command of Col. Randolph Bolger. It had become clear that Longstreet was rapidly marching on Vidalia, a riverboat landing just across from the Nationalist strongpoint of Natchez. In the course of the war, Vidalia had been fortified and for months the two towns had cannonaded one another. Both towns were less than 90 miles from Baton Rouge. With Vidalia in his control, Longstreet would be in a position to swiftly move towards the state capital, the last major town before New Orleans itself.
The Marquez plan was to use Bolger's brigade to make contact with Longstreet's much larger force, skirmish, and then rapidly withdraw towards Vidalia, hopefully luringi Longstreet into a rapid pursuit that would be unaware of the presence of Garcia and Post. The latter two forces would attack the Nationalist army on its flanks, trapping Longstreet against the River and defeating him
The plan might have succeeded, save for one of those random events that sometimes alter the course of history. Longstreet had sent out a number of reconnaissance patrols seeking the most usable way through the woods and marshes to their objective. (Maps had proven to be poor to useless in this part of Louisiana.) One of these patrols had several “swamp hunter” scouts in their ranks. On the afternoon of November 1st, two of of these backwoodsmen decided to supplement their rations by doing a bit of hunting. ( As volunteers, they took military discipline somewhat casually.) As they lay concealed along a stream waiting for game to come down to drink, a platoon of one of Bolger's brigades came from the opposite direction and proceeded to make camp very close to where they lay hidden. The sharp-eared scouts could overhear enough to learn that this platoon was part of a much larger force looking for Longstreet. After dark, they slipped away, so quietly that the Federal pickets heard nothing. A few hours later, Longstreet was told and reacted quickly, maneuvering so as to catch the Federals just at dawn. The result was a rout that broke Bolger's brigade into fragments. Men fled in all directions, leaving their breakfasts still cooking over their campfires. Far more importantly, in an officer's tent were found orders detailing the Federal strategy. Over the next week, Longstreet attacked first Post, defeating him and then wheeling westward, placed his main force between Garcia and Vidalia. The redoubtable James O'Hara brought his division by rail from central Mississippi, crossing the big river on the night of the third.
When O'Hara's men arrived around midday on November 5, he planned a flanking attack on the Mexicans who were concentrating their attention on Longstreet. Longstreet, had earlier ordered a reconnaissance in force be conducted to survey the ground in front of him. By 6:30 p.m.
O'Hara's force moved forward against the troops of the La Patria Division, but Longstreet ordered them withdrawn at 8:30 p.m. Since he now had a better idea of the terrain and enemy soldiers in the area. On the next day, Longstreet's preparations paid dividends, as his artillery was a major factor in helping O'Hara resist a Mexican counterattack, and he capitalized on the enemy confusion by launching an attack of his own. The following day, November 7, was one of Longstreet's finest performances of the war. Garcia came to believe, due to an adjustment in lines, that O'Hara was starting to retreat and attacked. Longstreet took advantage of this by launching a massive assault on the Mexican left flank with over 10,000 men. For over four hours they "pounded like a giant hammer"with Longstreet actively directing artillery fire and sending brigades into the fray. Longstreet and O'Hara were together during the assault and both of them came under artillery fire. Although the Federal troops put up a furious defense, Garcia and the remains of Post's Louisiana Rifles were forced finally to retreat. Vidalia fell the next day. The way southwards to Baton Rouge lay open. Longstreet gave much praise to James O'Hara's “alacrity and boldness.” who in turn credited the victory to Longstreet's use of a strategic model that general believed to be ideal—the use of defensive tactics within a strategic offensive.
