From Liberalism: In the Classical Tradition — surrounding passage

Parents are obliged to send their children to school for a certain number of years or, in lieu of this public instruction at school, to have them given equivalent instruction at home. It is pointless to go into the reasons that were advanced for and against compulsory education when the matter was still a live issue. They do not have the slightest relevance to the problem as it exists today. There is only one argument that has any bearing at all on this question, viz., that

“Continued adherence to a policy of compulsory education is utterly incompatible with efforts to establish lasting peace.”

The inhabitants of London, Paris, and Berlin will no doubt find such a statement completely incredible. What in the world does compulsory education have to do with war and peace? One must not, however, judge this question, as one does so many others, exclusively from the point of view of the peoples of Western Europe. In London, Paris, and Berlin, the problem of compulsory education is, to be sure, easily solved.