The powers not delegated to the United States by the Constitution, nor prohibited by it to the states, are reserved to the states respectively, or to the people.
This amendment does not make a lot of sense unless your thinking lines up with the founding fathers in that the primary power belongs to the people, secondary is the States and finally the Federal authority. Currently this seems to be upside down. The federal authority dictates to the states and both seem to try to dictate to the citizens. This is odd given the clear language of the amendment which seems very much to want to put the federal government’s power forward as limited and within certain bounds. Outside those bounds, the states and the people were to retain their power respectively.
People then might ask what those limitations might be but the preamble actually gives six things that the constitution was proposed to provide for: 1) Form a more perfect union, 2) Establish justice, 3)Ensure domestic tranquility, 4) Provide for the common defense, 5) promote the general welfare and 6) secure the blessings of liberty. Outside these things, then the states were to handle things and the people themselves.
If there is a flaw it might be the interpretation of people of these six things and how that interpretation might change over time. At the same time from the standpoint of the founders these things were concretely understood. It is people who have changed not what the founders intended as the desired powers of the federal government. The tenth amendment has an assumption of what the powers the federal government was granted and then gives over the rest of rights and powers to the states and the people.
The ninth and tenth amendment have one thing in common. They both are about protecting the liberty of the people. The Ninth amendment protects the rights not specifically stated in the constitution that the people possess and then the tenth comes along and preserves their powers.
The main problem I see in society in relationship to these two amendments is not just that state rights are under assault which is true in many ways, but even more so the rights and power of the people are under even more assault than the rights of the states. Parents are losing their right to raise their children as they see fit. Families often lose their power to live as they see fit and both state and federal powers seem bent on stealing these basic freedoms away. I can’t even begin to talk about individual rights that have been violated as the list is very long. The point of these two amendments is that if a dispute comes up between who has the power here, the judgment should ere as much as possible first to the side of the people and then the states before the federal government gets involved.