The Constitution says that the States all have to respect each others' laws. The respect has to do with the things written in the Constitution and the Amendments. The States all adopted the Federal Constitution as their own when they were accepted into statehood.
The States are separate nations that are governed by the Federal Government nation. Everything is done by agreement.
The 9th Amendment says:
In other words, the people retain all the rights they always had before Government came into existence.
Federal Government was there to protect the nation from foreign nations, and to decide squabbles between States. It isn't there to do anything with the people. But the people have freely contracted with the Federal Government this way and that, and that's why Government gets in our face at times.
If we use the 9th Amendment in court, and if we get a jury trial according to the 6th or 7th Amendments, and if we stand as a man or woman unrepresented, we can beat almost all Government laws.