On matters of teacher loyalty and conscience, World War I marked a legal watershed in the United States. During this conflict, schools became seminaries of patriotism and teachers had to promote loyalty and allegiance to the government. Throughout the nation, overzealous school boards imposed state‐legislated loyalty oaths upon teachers. In cities and rural communities, many teachers were accused of disloyalty, regardless of personal beliefs, and stripped of their positions. Teachers who criticized the war faced intense scrutiny and often were dismissed on the flimsiest of charges. Some teachers chose to litigate the matter in courts of law. Some were successful, and some were not. This pattern has continued during subsequent wars. In terms of free speech protections for public schoolteachers, the law has been applied inconsistently. Whereas college and university teachers have had some degree of constitutionally protected free speech because of the ideal of academic freedom, the same does not apply to public schoolteachers. This article traces a number school trials as well as court cases from World War I to the present. It examines how the judiciary has adjudicated acts of conscience during wartime in the nation's public schools. It remains an unsettled issue in need of constitutional redress.