A legitimate action!
On rare occasions, perhaps once a year, the Federal government does something it was meant to do. The rest of the time, the Feds are doing millions of things they were NOT supposed to do, and utterly failing to do things they should be doing.
Here's one of those rare exceptions: Breaking a levee along the Mississippi. This saves Cairo in Illinois while ruining a large amount of Missouri farmland.
The states were quite properly protecting their own interests, but the river doesn't give a shit about boundaries. So a larger organization was needed to settle the question quickly. And amazingly the Feds did settle the question using proper morality (save people before land); then they acted decisively in time to save Cairo.
More specifically, this is a once-in-a-lifetime example of a Fed
court handling a case that was meant to be in Fed court
jurisdiction as defined in the Constitution.