This thesis aims at understanding the choice of terrorism in mass dissident movements and the outcomes of civil resistance campaigns that coexist with the use of terrorist tactics by radicals. Towards this end, it focuses on dissident organizations and conflict dynamics and therefore contributes to the existing literature on terrorism and conflict, both methodologically and theoretically. Study one investigates the conditions under which groups that participate in mass dissent choose to initiate terrorist campaigns. I find that groups involved in either civil war or mass civil resistance might face strategic constraints that encourage them to resort to terrorism, due to perceived lower costs and higher tactical effectiveness. These constraints are higher repression and longer duration of mass dissent. Study two contributes to the literature on ‘radical flanks effect’. I find that terrorism generates incentives for the state to accommodate civil resistance movement, especially if nonviolent movements have a centralized leadership and hierarchical structure and can thereby credibly commit to nonviolent discipline and to avoid the escalation of the conflict to large-scale violence. Study three focuses on international support to rebel groups as determinants of the variation in the portfolio of killings across rebel groups. I find that rebels that receive financial support from external non-state actors are less likely to target civilians than combatants. This is because investing financial support domestically is more economically efficient and increased rebel dependency on the local population generating incentives to restrain the use of terrorism. In turn, rebels that receive military support from external non-state actors are more likely to target civilians than combatants. Military resources are efficiently invested in warfare activities without the need to increase reliance on the population. To test these mechanisms empirically, I model the portfolios of killings of rebel groups as a proportion of terrorist-related deaths and battle-related deaths
