During the Civil War, President Lincoln concerned himself with anything that might allow the Confederacy to sustain its war effort. Texas presented two problems to the federal government: a potential French alliance and the Confederate cotton trade in the Brownsville-Matamoros area. The Lincoln administration sought to neutralize both the dangers by occupying the Lone Star State. This task was left up to Gen. Nathaniel P. Banks, commander of the Department of the Gulf. Banks eventually launched four expeditions toward Texas, all four of which aimed to establish a sizable Union force there, partly to intimidate the French in Mexico. The third, the Rio Grande expedition, also had the formidable assignment of blocking the lucrative Confederate cotton trade.

The campaign began with an unopposed landing at the mouth of the Rio Grande on November 2, 1863. By the end of December, the Federals controlled the Texas coastline from Brownsville to the Matagorda Peninsula. Before moving up the coast, Banks contemplated linking up with Brig. Gen. James H. Carleton, commander of the Union forces in new Mexico. This move would have given the Federals control of the Rio Grande from Brownsville to El Paso. Distance, however, made such a project impracticable. Guarding 804 miles from Brownsville to El Paso would have required many more regiments than the Union could spare. Even a daring commander would hesitate to launch such an operation in the drought-stricken region along the Rio Grande. Banks opted for coastal operations because he knew the Texas shoreline was more vulnerable than the Rio Grande border. He expected to then penetrate the Texas interior, capturing cities such as Houston, San Antonio, Austin, and Galveston, thus crushing the civilian and military resistance. This would have accomplished the diplomatic and economic goals of the Rio Grande expedition. Unfortunately for Banks, his vision of conquering Texas from the coast was not shared by his superior, General in Chief Henry W. Halleck. Halleck, who opposed the Rio Grande Campaign, pressured Banks in January 1864 to switch to the Red River route into Texas.

Despite Halleck's reluctance to push deeper into Texas from the coast, the Rio Grande expedition had already achieved some of its objectives. Diplomatically, Banks established a significant Union presence in Texas for the French to consider. Second, the export of Confederate cotton, though not severely crippled, was slowed. The Confederates were forced to divert the cotton to the upriver ports of Laredo and Eagle Pass, where the traffic continued to be quite heavy, but the increased distance over which the trade items had to travel added greatly to their cost. This caused considerable distress for the Confederate commanders who were waiting to receive valuable supplies. Politically, the expedition placed into power A. J. Hamilton, whom Lincoln had appointed as military governor of Texas in November of 1862. Perhaps the strongest civilian advocate of a Union occupation of the Lone Star State, Hamilton arrived in Brownsville in December of 1863 to begin his duties. With Federal forces occupying only the Texas coastline, however, his political power did not extend to the state's major population centers.

The presence of Federal troops on the Texas coast had a sobering impact on Texas' civilian and military population. Texans believed that the heavy hand of war they had read about in other theaters had finally come to their state. Texas newspapers, especially the Houston Tri-Weekly Telegraph, wrote about the great fear and anxiety the invasion generated. One account described the situation on the middle Texas coast this way: We and the entire country [are] in great excitement. The majority of planters have removed their negroes towards the interior, and many families have left them all behind, in fleeing from the perils of invasion. We see families flying in every direction from the coast. The people feel they have nothing to hope for [and pray] that the scenes of outrage perpetrated in Louisiana will not be reenacted in Texas. Apprehension also developed as far inland as Austin, where a newspaper reported that Their purpose is evidently to overrun Texas, and the occupation of the capital will be their first object.

Confederate soldierstoo were discouraged during this operation. Nothing illustrates this better than their letters. One trooper stationed near Houston in the spring of 1864 wrote the following report: Cannonading heavy off the coast. Boom upon boom shakes the solid ground. Have to fight soon I suppose. I have a hell of a headache tonight. This day has been cloudy and cold winds. I spread my blankets and fall recumbent on my hard pallet. My poor and pensive soul is weighed down at seeing our nation in tears and trouble.

Morale, with few exceptions, was never a serious problem among the Federal soldiers in Texas. Since the summer of 1863, the Union armies had achieved great victories, and this instilled a sense of pride in the Federal units. A good example of this appeared in a newspaper published by soldiers at Brownsville, the Loyal National Union Journal. The paper regularly reported the sense of dignity the men maintained, despite the fact that they were the Union's most distant and isolated fighting force. The paper pointed out that the men in the Union armies were the very foundation of the war effort. Their work, even though by the spring of 1864 it was primarily occupation duty, was still a major contribution to the eventual defeat of the Confederacy. In their own eyes, they were a distinct breed of men who deserved the respect and admiration of a grateful nation.

Although soldiers in the Union ranks maintained a relatively high morale, some of the generals associated with the expedition became decidedly uneasy by the spring of 1864. Many of them believed all of Texas might fall that year. Maj. Gen. Napoleon J. T. Dana, who briefly commanded the XIII Army Corps, supported more aggressive military action in Texas. He maintained that the inactive status of the Union troops on the Texas coast caused these veteran soldiers to lose their fighting edge. Another prominent officer associated with the expedition, Maj. Gen. C. C. Washburn, also wanted to continue the successful march up the Texas coast and requested additional troops and supplies. Unfortunately for the Union, by the end of December 1863, the Rio Grande campaign had ground to a halt. Federal operations on the Texas coast would not be expanded.

Standing in the way was General Halleck's insistence that the Red River was the best route for an expedition into Texas . The death blow to the Rio Grande campaign came in March 1864, when the new general in chief of all U. S. armies, Ulysses S. Grant, ordered the abandonment of the entire Texas shoreline except for the Brownsville area. As long as the French were in Mexico, Lincoln wanted a Union force kept in the Lone Star State, even a small one. Banks, not wanting to tip his hand to the enemy, actually kept Federal soldiers on the Texas coast until June, thus preventing an immediate transfer of some of the Confederate troops from Texas to Louisiana. This move, he hoped, would increase the chances of military success in Louisiana.

Unfortunately for the Union, the Red River campaign failed, and Banks, as commander of the Department of the Gulf, had another defeat marked against him. After his important victory at Port Hudson, nothing went right for Banks. The strike at Sabine Pass and the Texas Overland expedition had both failed in their attempts to penetrated Texas in 1863. When Banks successfully occupied the lower Texas coast in the fall of that year, his immediate superior, General Halleck, refused to provide logistical support of continued operations. Halleck's obsession with the Red River route into Texas undermined the possible success of the Rio Grande expedition. A common criticism leveled against many Union generals during the Civil War was their failure to follow up their victories by relentlessly pursuing the enemy army until it was completely destroyed. When Banks attempted to extend his success in Texas, Halleck refused any further support for the Rio Grande operation. Banks had generals under him who not only had good combat records but also were confident of victory in the Lone Star State. General Dana, in particular, knew South Texas fairly well, having been stationed near Corpus Christi during the Mexican War.

Another reason for the failure of the Rio Grande expedition was Halleck's low opinion of political generals. Halleck told General Sherman that Banks's operations in the West are about what should have been expected from a general so utterly destitute of military education and military capacity. It seems but little better than murder to give important commands to such men as Banks, Butler, McClernand, Sigel, and Lew Wallace, and yet it seems impossible to prevent it. In May 1864, Halleck also suggested that Grant petition Lincoln to replace Banks as military necessity. Halleck knew that Banks was a political asset to Lincoln but realized that a request from Grant for a reorganization of the Union command west of the Mississippi would carry more weight. Even before Grant received Halleck's letter, he had suggested to Halleck [on April 25] that Banks be replaced by Maj. Gen. Joseph Reynolds, then commander of the New Orleans defenses. The petitions for Banks's removal by Grant and Halleck forced Lincoln to make a politically difficult decision. On May 8, 1864, he appointed Maj. Gen. Edward R. S. Canby to command the newly created division of West Mississippi, which encompassed the Department of the Gulf and the Department of Arkansas.
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The Rio Grande campaign, an often-overlooked chapter of the Civil War, led to the only sustained occupation of any part of Texas. The Federal army disrupted the cotton trade, discouraged French meddling in the war north of the Rio Grande, and installed a military governor, Andrew J. Hamilton. In the postwar period, many of these Federals served with the occupation forces along the Rio Grande. The expedition also created a fear among soldiers and civilians that the ravages of war had now descended upon the Lone Star State. Civilians along the Gulf coast and up the Rio Grande Valley knew all too well that the Civil Ear had arrived.

Of Banks's four campaigns against Texas, only the Rio Grande expedition led to any significant Federal presence on Texas soil for an extended period of time. Although most of Texas remained unconquered during the Civil War, the blame should not fall on the soldiers of the Department of the Gulf, most of whom were seasoned veterans. The men associated with the Rio Grande operation did their duty well despite the fact that they were not led by a successful general or involved in a famous battle. Dispute over strategy between Banks and Halleck doomed the Rio Grande campaign. And even though General Grant ordered the abandonment of the Texas operations in the spring of 1864, he maintained a thousand-man force at Brazos Santiago until the end of the war. When the war in the East ended, Grant's only major concern west of the Mississippi was the presence of the French in Mexico. He feared a continuation of the war south of the Rio Grande since so many Confederates had fled to Mexico. As a result, the garrison at Brazos Santiago provided a valuable service to Grant at this time. The troops there monitored the international border and reported any suspicious activity to the Union high command.

In the final analysis, the sustained occupation of Texas, achieved only by the Rio Grande expedition, warned against French flirtations with the Confederacy out of Mexico. By planting the American flag in Texas and keeping it there until the end of the war, the Lincoln administration was able to concentrate on defeating the Confederate forces east of the Mississippi.