Answer:
Little of the debate over slavery's expansion affected the tribes in Indian Territory. However, Indian slaveholders were apprehensive about the Republican victory in 1860 and the party's ultimate designs for "the peculiar institution." Many Indian Territory residents were upset by Secretary of State William H. Seward's remarks when he urged the U.S. government to extinguish tribal land titles and open the West to settlement.
Albert Pike thus made headway with the Indian Territory tribes. He signed treaties with the Creek (July 10, 1861), the Choctaw and Chickasaw (July 12), the Seminole (August 1), and the Wichita, Caddo, and others (August 12). John Ross stalled, but the military power of the Confederacy rose while that of the Union waned. On October 7 the Confederacy consummated a treaty with the Cherokee and then with the Quapaw, Seneca, Shawnee, and Osage. The mixed-bloods rejoiced over the alliance and quickly signed into the Confederate military.
In terms of tactics the determining factor in the West during the Civil War was the Mississippi River. Union strategy, devised by Gen. Winfield Scott and dubbed the "Anaconda Plan," sought to control the Mississippi River and thus to divide the Confederacy. Most of the warfare in the West, therefore, was connected to furthering or thwarting Brig. Gen. Ulysses S. Grant's advance down the river. Military activity in Indian Territory was marginal to that objective. Confederate Brig. Gen. Ben McCulloch, that army's second-ranking general officer, was ordered from Texas to Arkansas and placed in command of Indian Territory. The Confederate Army of the West, which he was to build, was to be composed of three Indian regiments plus one regiment each from Texas, Louisiana, and Arkansas.
After the treaty making ended, Confederate military companies formed rapidly among the tribes, but resentment toward the Confederacy also surfaced. The Creek leader (and slaveholder) Opothleyahola rejected the Confederate alliance and led some seven thousand followers away from tribal lands. Secessionists perceived him as an enemy, and they pursued, under the leadership of Col. Douglas H. Cooper. The Creeks defended themselves at Round Mountain (November 19, 1861), Chusto-Talasah (December 9), and Chustenahlah (December 26). In the last engagement, Opothleyahola's encampment was routed. The remainder of his followers eventually reached Kansas as refugees.
Confederate leaders attempted to use Indian Territory troops to force the federals out of Arkansas. Under Albert Pike, promoted to brigadier general, the Indian regiments joined divisions led by Brig. Gens. Sterling Price and Ben McCulloch to drive out Union troops under Brig. Gen. Samuel R. Curtis. However, at the Battle of Pea Ridge (March 7–8, 1862), Curtis proved the superior strategist and defeated the Confederate command. Pike, upset by McCulloch's charges that the Indian troops had performed in a disorderly manner and had scalped Union soldiers, took his regiments back to Indian Territory. He resigned his commission in May 1862 because in his view the Confederates were failing to uphold their treaty promises. Also in that month the Trans-Mississippi Department of the Confederacy was created, specifically including Indian Territory.
After Honey Springs the Civil War in Indian Territory assumed a different form and was, in truth, a minor affair. The fate of the region became similar to that of border areas like Missouri, Kentucky, and Tennessee. Rule of law was lost, and roaming bands of irregular partisans plundered and murdered hapless civilians. William Quantrill and his company of irregulars made their way several times through the land. Stand Watie was active in these years, but he was no guerrilla. Promoted to brigadier general in May 1864, he undertook military missions of strategic value that sought to disrupt the supply lines of Union troops that were stationed in Indian Territory or were moving south. His most famous exploits were the capture of the steamer J. R. Williams on June 15, 1864, and his seizure of a Union supply train at Cabin Creek on September 19, 1864.
The tribes unsuccessfully attempted to reclaim the advances made between 1840 and 1860. Although wartime animosities flared between the old Confederate and Union factions, new governmental entities were formed as a spate of constitution making occurred between 1867 and 1872. Railroads penetrated Oklahoma in the 1870s, but in some ways their arrival was a curse rather than a blessing, for they brought whites seeking land.