This research develops a novel model for external actors' support for separatists.Three variables measuring external actors' support are identified through two case studies, Kosovo Liberation Army and Liberation Tigers of Tamil Eelam, with an emphasis on Military Aid's impact. The variables are then applied to a quantitative analysis of external actors' support in a dataset of 75 observations during the years 1991-2020, utilizing the Uppsala Conflict Data Program External Support Dataset. The findings for this research show that Military Aid and Moral Support improve the probability of survival for a separatist group. A deeper analysis reveals that military aid among the three major powers (People's Republic of China, United States of America, Russian Federation) does not have a greater impact. Finally, the PRC's Moral Support has a stronger impact than the USA's and RF's Moral Support.

What role does foreign support play when an insurgent group adopts terrorism? Utilizing both quantitative analysis and in-depth case studies, this thesis examines the effects of foreign support among other commonly cited explanations for an insurgency's adoption of terrorism. In addition to observing the effects of foreign support on the adoption of terrorism, the effects of government regime type, insurgent group goal type, insurgent group strength, and foreign benefactor type are analyzed. After executing a multiple logistic regression analysis of 109 intrastate conflicts occurring from 1972 to 2007 and conducting detailed case studies for the Tamils in Sri Lanka and the Kurds in Iraq, this thesis concludes that specific types of foreign support from non-state actors not only make insurgent groups significantly stronger but also make them more likely to adopt terrorism thus calling into question the weapon of the weak argument.

In asking what factors better allow foreign terrorist organizations to become global, I propose the question: in what ways and why do foreign terrorist organizations become transnational in the post-Cold War era? This research will then evaluate the strategic use of group identity – specifically ethnic, religious, and ideological – by foreign terrorist organizations in order to best determine whether or not these groups, based on their respective identities, possess the ability to become transnational. Identification with these group identities garners advantages that terrorist organizations otherwise could not, aid such groups in their expansion beyond traditional state borders, and assists in the transition towards more transnational states of being. In addressing the saliency of group identity within the broader context of international terrorism, the global community will be better suited to direct counterterrorism efforts towards the most threatening and transnational foreign terrorist organizations in regards to their tactics, strategies, organization, and networks.