There is a broad consensus on the legitimacy of states to control immigration. However, this belief has recently been questioned, among other reasons, due to the contradiction with current practices in emigration and internal mobility. The principle of symmetry states that any restriction on immigration should also apply to emigration; or that, to the contrary, if there is a right to emigrate, there should be a corresponding right to immigrate. The principle of coherence posits that every reason one might have (...) for moving within a country also counts for moving between countries. This article proposes to extend the coherence principle from external to internal migration, arguing that the same reasons that justify restrictions on mobility across borders justify restrictions on mobility within borders too. Therefore, either freedom of movement is a fundamental right or the right of the political community to control mobility prevails. The interests at stake are in both cases the same, so asymmetry is not warranted. This leads us to an apagogical argument for open borders. (shrink)