The precariousness of their relationship with the Dakota was evidenced in 1843, when "the Omaha and the Ponca were considering a union, 'to live together as one people' [….] no doubt as a defensive strategy against the Dakota" (Wishart 1994, 85). However, this ultimately never came about, "and the Ponca again joined the Dakota to raid the Omaha," because "in the chaotic years of the 1840s when starvation confronted all the Indians, warfare became the primary means of the spreading the subsistence base," and allying with the Dakota, who were one of the most powerful tribes in the region, made the most sense (Wishart 1994, 85). Despite the Ponca's alliances with the Dakota, the latter group became increasingly hostile, resulting in the Ponca gradually returning to their ancestral base near the mouth of the Niobara river, "likely [because] the Dakota had cut them off from the bison range and forced them to turn back to corn farming for their food" (Wishart 1994, 84). Even then this was short-lived, as "by the second half of the 1840s the Ponca were again spending more time in tipi encampments and earth-lodge villages" spread out along the Niobara, and once again, they turned to the United States and its westward-aiming settlers for assistance (Wishart 1994, 84-85). For example, in the winter of 1846 to 1847, the Ponca "persuaded two hundred Mormons […] to stay with them on the Niobara," because "the Mormons provided a measure of protection against Dakota war parties [and] their possession of a small cannon seems to have been particularly influential in the Ponca's decision to extend the invitation" (Wishart 1994, 85). However, like before, this brief period of calm was overshadowed by the larger famine caused by inclement weather and the decimation of the bison herds, so that by the 1850s, the Ponca were once again forced to give up much of autonomy in return for the protection offered by the United States' government.

Despite the fact that "the relative gradual population loss among the Ponca indicates that they fared better than any of the other Nebraska Indians" from 1837 to 1855 (the population decreased from around 800 to near 700 during this time period), by the 1850s, "the Nebraska Indians continued to starve and die at the hands of the Brule and Oglala Dakota," and the various tribes, including the Ponca, sought or were convinced to take the assistance offered by the United States government, but this time it would come with a much higher price (Wishart 1994, 72, 84, 102). One may view each successive treaty between the Ponca and the United States as the latter taking greater and greater advantage of the former's increasingly dire circumstances. Thus, where the 1825 treaty only required that the Ponca "admit" the supremacy of the United States and work to ensure its economic interests, the treaty between the Ponca and the United States in 1858, like the other treaties signed by Nebraska Indians during the same decade, required that the Ponca give up ownership of large swaths of their land. "Having been brought to the brink by American expansion, they were now obliged to sell their territories just to relieve their poverty," and so "the Ponca sold a wedge of country stretching from the mouth of the Niobara north into what is now South Dakota, and were assigned a reservation of about 58,000 acres between the Niobara and Ponca creek" (Wishart 1994, 102).

More so than the previous treaties, the treaty of 1858 demonstrated just how fully the Ponca were at the mercy of the United States and its representatives, especially because the other Nebraska tribes had already or were in the process of negotiating their own treaties. In December of 1857, the Ponca delegation to Washington, DC, "drew up a proposal detailing what they wanted in exchange for their lands" in the hopes of retaining their ancestral home as well as gaining the money and supplies they would need to ensure their future success (Wishart 1994, 134). At first the Ponca "defined their territory as extending from the Missouri at Aoyway Creek to the White River and west to the Black Hills, an extensive claim that both they and the commissioner knew was challenged by the Omaha and Dakota," and requested "payments of forty thousand dollars for each of the first ten years, half of this to be...

By the end of the negotiations, however, the Ponca were reduced to "plead[ing] with the commissioner not to move them from their ancestral homeland bordering the Missouri, between Ponca Creek and the Niobara [….] but the Indians' pleas and arguments were to no avail," so that "when the treaty was signed on March 12, 1858, the Ponca received only a fraction of the payments they had requested [….] and were given a year to move twenty-five miles up Ponca Creek to the rugged tract of land that was reserved for their future home" (Wishart 1994, 134-135). Far from offering the Ponca a means of ensuring their survival, the treaty ended up almost destroying them altogether.
Firstly, the treaty ignited the fury of the Brule, "and they sent word promising to wipe them out, along with those other turncoat treaty Indians, the Omaha and Pawnee" (Wishart 1994, 135). In 1859, after the Ponca had already suffered from continued starvation as a result of a poor summer hunt and the fact that "the land on the valley floor that they had customarily farmed was occupied by settlers," the Brule attacked, and "nearly all the Ponca's tipis were destroyed, their horses taken, their meat burned [and] the Brule even cut their moccasins into pieces" (Wishart 1994, 135-136). The prospects at the new reservation were no better, because "much of the land was rugged, there was no local hay for their horses, and good soils were restricted to the narrow river terraces" (Wishart 1994, 137). Furthermore, while one of the ostensible goals of the treaty was to ensure protection from the Dakota, "the reservation was remote," and its "only proximity was to the Dakota" (Wishart 1994, 138). Over the course of the next five years, the Ponca suffered from continued starvation and attacks from the Dakota, and once again considered allying themselves with the Omaha, but were ultimately reluctant as this would constitute a further loss of sovereignty, land, and access to their ancestral home.

In what was perhaps the last glimmer of hope for the Ponca, in 1865 "the Indian Office decided to reward the Ponca for their 'constant fidelity' by returning to them their 'old burial grounds and cornfields' near the mouth of Ponca Creek," so that "on March 19, 1865, the Ponca were given back the country lying to the east of the their reservation and bounded by Ponca Creek and the Niobara and Missouri Rivers" (Wishart 1994, 147). This return to their ancestral land saw an immediate uptick in the Ponca's fortunes, but this was short-lived, because although the newly restored area featured useful soil and far more abundant food, they were eventually displaced for good, once again through the combined efforts of the Dakota and the United States.

The history of the Ponca's gradual loss of land and sovereignty over the course of the nineteenth century was largely due to the combined influence of the Dakota and the United States, and in 1868, these forces allied to evict the Ponca from their ancestral land for good, but it occurred through the kind of bureaucratic injustice that would come to characterize the difficulties faced by Native American Indians in the twentieth century, because "the Ponca's greatest tragedy […] and the United States' greatest injustice […] took place less dramatically and without any apparent notice" in 1868, when the Dakota and the United States signed their own treaty. "The Dakota ceded their vast hunting grounds and agreed to settle on the Great Sioux Reservation west of the Missouri River in Dakota Territory," but in an "incredible oversight," "in the southeast the reservation was delineated by the Missouri River and the northern line of the state of Nebraska, which ran along the Niobara," thus atoumatically including the Ponca's reservation in the land promised to the Dakota (Wishart 1994, 153). Thus, while the Ponca were already suffering under Dakota attacks and a lack of promised support from the United States as laid out in their 1858 treaty, the signing of the 1868 treaty meant that the Ponca's "right…