I would argue that incorporation was the beginning of the death knell of states' rights, followed by the dramatic expansion of the administrative state in the early 1900s.
The fact that they needed to supervise them because not enough was being done to change the cops behavior is a strong argument that the federal government should be doing it
> I would argue that incorporation was the beginning of the death knell of states' rights
People have rights. States which are government do not have rights. The idea of states rights is a ridiculous one that was frequently used to try to justify lack of federal oversight and the "right" to oppress people's rights.
As for incorporation it's one of the best actions the supreme court has taken. As a libertarian you should be happy the court said that states can no longer violate people's constitutional rights
I would argue that the death knell for the state's rights reading of the Constitution was the Civil War. It's fairly clear that the development of the government post-war, especially illustrated by the punishments levied against the southern states, created a national government rather than a federation of allied parties.