Abstract
Some have argued that the right of national self-determination gives every national group the power to decide for itself whether to remain part of an existing state or to secede unilaterally and form its own state. Such a theory underpins the claim that Quebec is entitled to decide on its own whether or not to leave Canada. This paper examines the main philosophical arguments for the theory and finds them one-dimensional and inadequate; they fail to take account of the full range of complex issues arising in actual cases of proposed secession. If the right of national self-determination is understood as involving a right of unilateral secession, it cannot be attributed to national groups across the board. It arises only in specific historical circumstances, usually involving oppression or other forms of grave injustice.