In times of crisis, confrontations between the government and political groups often spill over into the court, and the trial becomes a means of denying the authenticity or true nature of the defendants' activities. Although British trials are based on an adversary system, there is great pressure to minimize this form so that the outcome is arranged beforehand and the trial only appears to be a contest. Defendants who view themselves as political then try to manage this type of trial so that it promotes their political activities. This study focuses on the law breaking and trial activities of the WLS, beginning with the 1936 trial of three Welsh National Party men who set fire to a Royal Airforce aerodrome at Pendros and then surrendered to the police. The ensuing trial, in which the defendants tried to politicize the proceedings while the Government sought to maintain their criminal character, displayed many elements that were to characterize the WLS trials of the 1960's and 1970's. The WLS was formed in 1962 and launched the first of several campaigns of civil disobedience centering on the language issue the following year. In this and later confrontations, police response was low-key; WLS members deliberately broke laws so that a court trial could be used for propaganda purposes, and some segments of the Welsh intelligentsia supported the movement. The British Government passed the Welsh Language Act in 1967. In the late 1960's, the WLS initiated a campaign for bilingual road signs; an issue superceded by protests against the investiture of the Prince of Wales in 1969. The culmination of these activities was the 1971 trial of eight WLS members on conspiracy charges. In this and in later trials, the judiciary insisted that the proceedings were criminal but imposed relatively light sentences. Although WLS success as a pressure group was impressive, its activities declined after 1974. Additional research into the causes of political trial activity should look beyond this group into broader realms of Welsh society. The article contains 10 footnotes and 16 references.