The end of the Cold War brought with it the failure of a number of states. Among these was Afghanistan. During the 1990s, humanitarian tragedies, often caused by the collapse of nation-states, became a concern in Western countries, but mostly as humanitarian problems. The events of September 11, 2001, however, moved failed states to the forefront of the security agenda. Al-Qaida s decision to operate out of bases in Taliban-controlled Afghanistan gave the problem of failed states a new relevance and suggested that these could constitute a threat to international security. As the terrorist attacks manifested that terrorism stemming from failed states knew no borders, this suggested that preventing states from failing, and rebuilding those that had failed, were now strategic and moral imperatives. Against this background, this thesis investigates how three Western governments approached Afghanistan and constructed their security policies after September 11, 2001. By using Afghanistan as an example, the aim of this thesis is to examine how the issues of failed states and state-building entered and have influenced Western security policy agendas. This is done by analysing the rhetoric behind the U.S., British, and German decisions to engage in Afghanistan by means of a discourse analysis. These countries have been chosen as units of analysis because they are the largest troop-contributors in Afghanistan and because their security policies are based on diverse historical experiences and national security cultures, which may provide interesting insights into how different Western states have approached Afghanistan. My research strategy has two elements: First, the thesis investigates how the Western governments regarded the threat from failed states. Second, this thesis examines the rhetoric behind the governments decisions to engage in Afghanistan in light of realism and liberal internationalism. The purpose is to discover the motivations and legitimations for the decisions to engage in Afghanistan, and examine whether and how the theories can explain the governments´ policies on Afghanistan.