The U.S. Supreme Court case Missouri v. Nebraska; Nebraska v. Missouri in 1904 revolved around a dispute between the two states regarding their shared border along the Missouri River, which had shifted over time due to natural changes in its course. The main issue was whether these changes were caused by avulsion (a sudden change) or accretion (a gradual change). This distinction is significant because under common law principles, if a river boundary shifts gradually through accretion, then state boundaries shift with it; but if it shifts suddenly through avulsion, then original boundaries remain intact despite where the river now flows. After examining historical evidence and hearing expert testimony on how rivers naturally behave and alter their courses over time, the court ruled that most of the disputed area belonged to Nebraska as they concluded that most of these alterations were due to slow processes of erosion and deposition rather than sudden events like floods or channel cutoffs.

The dissenting opinion in the case of Missouri v. Nebraska; Nebraska v. Missouri, 1904 was not specifically recorded or attributed to a particular justice. However, it can be inferred that the dissenters disagreed with the majority's decision which ruled in favor of Missouri over a dispute regarding their shared border along the River Des Moines and its changes due to avulsion and accretion processes. The dissenting justices likely believed that natural alterations should dictate state boundaries rather than adhering strictly to historical demarcations as decided by past treaties or agreements, thus siding more with Nebraska's argument for adjusting borders according to shifts in river courses over time.