The principle I am using is the original constitution which says that the federal governments powers are few and fixed, whereas state powers are many and undefined.
Right now, because of the 16th &17th amendments, the Butler Case (which said the federal government was no longer fixed and restricted to its original 20 powers), the office of president which before had not the power to make laws, is now by executive orders all over the place is creating laws and the Judiciary is also making laws rather that protecting the constitution. With all these things going on, protections for liberty are all but gone and there is no limit to the run away government arrogating power to itself.
Hopefully with the convention of states we can put a stop to all this corruption beginning with repealing the 17th amendment. With the passing of that amendment, the powers of the states became limited and defined by the federal government which is the reverse of what it should be. Senators were to supposed to be assigned by state legislatures to protect the states and Representatives to the House were to be elected by popular vote to give citizens representation, thus providing a balance to federal power and keeping the federal government answerable to the people. By making Senators elected by popular vote, they become agents for the federal government rather than agents for the state.
Where should auto safety standards come from? The states, because that had not been a power specifically defined for the federal government. An even better choice would be to let competition in the market decide.
That's my opinion and my hope is that the convention of states will be able to rectify this mess.
Several ideas in this one post:
1 - your interpretation of the constitution
2 - associating the shifting of roles with a reduction in liberties
3 - corruption
4 - safety standards
Again, i'm gonna stick with safety standards for now. It strikes me that a key role of congress has always been to make commerce as smooth as possible. From that perspective, universal safety standards can be seen as making interstate commerce much more efficient. So, far from being an overreach, it strikes me that federal safety standards are a huge boon to interstate commerce.
Now, I'd acknowledge that the roles of government have shifted over the years, but isn't that capability built into the original system?