From Lakota America: A New History of Indigenous Power, by Pekka Hämäläinen (The Lamar Series in Western History; Yale U. Press, 2019), Kindle pp. 123-124:
Lakotas had blended raiding and extortion with diplomacy and exchange into a flexible economy of violence that left the Arikaras weak and needy. Tabeau thought they saw in them “a certain kind of serf, who cultivates for them and who, as they say, takes, for them, the place of women.” The gendered language was carefully considered. Two generations earlier Oglalas had lived as farmers under Arikara tutelage, but now they were people of the hunt and ascending. While diminishing the Arikaras, they treaded carefully not to alienate them to a point of rebellion. Tabeau realized this and yet failed to avoid becoming a foil for Lakota stratagems. He complained bitterly how Lakotas, having returned from a trade fair on the Minnesota, “announce that merchandise is abundant and wonderful there, give in detail the price of each article and make the Ricaras understand that I treat them as slaves.” Lakotas were manipulating markets and perceptions to their advantage. While forcing Arikaras to pay inflated prices for their exports, they still managed to paint the St. Louis traders as the real exploiters and villains.
Outplayed by Lakotas, Tabeau struggled with the fallout. Hoping that Arikaras’ “customary mildness, long known, would induce the government and the traders to provide them constantly in the future,” he earmarked a good portion of his powder for them. It was too late. Arikaras denounced Tabeau as an outsider who had “seen them without breech-clout, without powder, and without knives” and yet had refused to share his wares. He faced constant insults and demands for largesse and, in the end, declared his bid to win over the Arikaras a failure. They were, he reported, “not a fit subject for a special trade expedition.”
That declaration began a long marginalization and vilification of the Arikaras, once one of the most renowned traders in the American interior. The vilification took time to take root, but once it did, it fixed the Arikaras in the American imagination as an irredeemable menace. It committed the United States to destroying them, inadvertently paving the way for a Lakota hegemony in the upper Missouri Valley.
Three thousand Arikaras had become virtual vassals of Lakotas, their economies and very lives remolded to accommodate the new masters of the Missouri. Tabeau wrote off the entire valley from the White to the Heart River—a 250-mile stretch of prime fur country—and shifted his sight to the Mandans farther north. “A post among the Mandanes,” he mused, “would be a gathering-place for more than twenty nations and would be the means in determining the Ricaras to take up a station nearby.” He envisioned a vast trade emporium extending upriver from the Mandans to embrace the Cheyennes, Crows, Shoshones, and many other people. The plan was as ambitious as it was improbable, for Lakotas would not allow it.