In the 1960s, a period characterized by the gradual closing of political space in South America due to the upsurge of authoritarian regimes, New Left armed organizations emerged to embrace political violence and transnational strategies as the only path to achieve social change. My project examines the transnational militant political culture that emerged from this constriction of political space, socio economic crisis and increased social polarization. It argues that leftist political violence can not only be explained merely as a structural response to political and economic constraints; it is also a result of contingent cultural definitions articulated by a new political generation of activists inspired by the emergence of an intellectual New Left and new cultural meanings about youth rebellion held by middle class sectors. By tracking the historical genesis of the political ideas, clandestine practices, cultural affinities, and strong emotions that constituted this political culture, my project seeks to explain how this political generation, which emerged from the increased social mobilization of the sixties, ultimately embraced guerrilla war as the sole means to achieve social change in their countries in the early seventies. My project travels through different national territories and focuses on the participation of militants from different countries, in critical local events, to understand the gradual development of a transnational network of armed organizations and its subsequent political culture. It uses a transnational frame of analysis to examine a topic that has so far been examined exclusively in national or comparative perspectives. Methodologically, my project engages with the inquiries suggested by oral historians regarding the relation between subjective experience and historical events, and with the social movement field regarding explanations for the use of violence by social movements in their conflicts with the state, and the role of emot