"But," it will be asked of the Anarchists at this point in the argument, "what shall be done with those individuals who undoubtedly will persist in violating the social law by invading their neighbors?" The Anarchists answer that the abolition of the State will leave in existence a defensive association, resting no longer on a compulsory but on a voluntary basis, which will restrain invaders by any means that may prove necessary.

The Relation of the State to the Invididual (1890)