"If migration is the same kind of thing regardless of whether it goes over a border, then certain things follow. Logically, if you support governments controlling movement across the borders, then you should support their having the power to control movement and residence within borders. Historically in fact this was normal, and governments did have that power (even if they found it hard to exercise it).
The egalitarian philosopher Brian Barry took this view, arguing both that the two kinds of movement were the same and that governments should have the power to tell people where to live. (The government might decide to allow free movement within the borders, but this would be a matter of policy not a recognition of a right.)
In other words, control of migration over borders is one aspect of a wider sovereign power to control and regulate movement and abode. The right of individuals to move within a state, if it is one that overrides and excludes any political power to control movement and residence, should also extend to a right to move across political borders — as long as you think that right is a natural one in some sense and not granted by a political community."