What overriding principle with respect to state and national citizenship was clearly established by the u. s. supreme court in the bradwell v. illinois and the slaughterhouse cases of 1873?

It was established that the privileges and immunities clause applies on a federal level in dealing with the federal government, but does not apply to the state government at the state level because of the two ideas of citizenship. It was explained that there is only a small amount of federally protected privileges and immunities and this was not one of them.