In the 1943 case Kansas v. Missouri, the U.S Supreme Court was asked to resolve a dispute between the two states over their shared border along the Missouri River. The disagreement arose due to changes in the river's course since an 1821 survey which had originally established this boundary line. Kansas argued that despite these shifts, legal precedent maintained that state boundaries should remain fixed at their original location. However, Missouri contended that when rivers serving as borders change naturally over time (a process known as avulsion), state lines should move accordingly. The Supreme Court ruled in favor of Kansas by a vote of 6-2, holding that while minor alterations in a river’s course can indeed shift boundaries (accretion), sudden and significant changes do not have this effect unless specifically agreed upon by both parties involved. Therefore, even though parts of what was once considered Kansas land now lay on Missouri's side of the river due to its altered path, it remained legally part of Kansas because there had been no mutual agreement for such territorial reassignment.

In the dissenting opinion for Kansas v. Missouri, 1943, it was argued that the Supreme Court should not have jurisdiction over this case. The dissenting justices believed that disputes between states regarding their boundaries should be resolved by Congress and not by the courts. They contended that such issues are inherently political in nature and thus fall outside of judicial purview. Furthermore, they expressed concern about setting a precedent where any state could bring a lawsuit against another state to resolve boundary disputes or other disagreements without first seeking resolution through legislative means. This would potentially open up floodgates of litigation between states which could overwhelm the court system and undermine its intended function as an arbiter of law rather than politics.