I've posed this question before. What possible constitutional topic could not be characterized as relating to the power distribution between the states and the federal government?
A subject so broad as to include everything would not and should not be considered a single topic.
And yet this "single topic" the corruption/destruction of the constitutional, vertical separation of powers as between the national government and the states goes straight to the root of all the difficulty. So, best to attack the root, not the branches and leaves higher up the tree.
You want tho kill a snake? Go straight to its head, and lop it off. Same difference....
"Keep your eye on the doughnut, not on the hole...."