$$ The national government and the states have authority over defined and mutually exclusive policy areas

$$ The Supreme Court should resolve conflicts between the authority of the national government and the states

$$ The national government should $1$n$1$t$1$ate policies and then turn them over to the states for administration.

$$ Any law passed by the national government $1$s the supreme law of the land.

$$ The national government and the states should share authority equally in all policy areas

What does the doctrine of dual federalism maintain?