The Security Implications of the Collapse of the Afghan Nation-State for Iran’s Eastern Border Security

The collapse of the Afghan government in August 2021 was not merely a regime change, but a comprehensive structural, political, and security breakdown that created a power vacuum and paved the way for the Taliban’s return to power. This transformation has had far-reaching implications for the security of Iran’s eastern borders. Since understanding these implications and identifying appropriate countermeasures are crucial for safeguarding national security, managing migration, preserving natural resources, and sustaining border livelihoods, the present study aims to analyze the effects of Afghanistan’s state collapse on the military, economic, social, and environmental security of Iran’s eastern borders, and to propose relevant policy responses. The central research question of this paper is: What are the security consequences of Afghanistan’s state collapse for Iran’s eastern borders? The main hypothesis posits that the post-collapse power vacuum and ensuing instability have intensified military, economic, social, and environmental threats along Iran’s eastern frontier. This qualitative and document-based research relies on library resources, scholarly articles, international reports, and credible media sources. Data were analyzed through textual content analysis and multidimensional security analysis. The findings reveal that the post-collapse period has witnessed the proliferation of terrorist groups, increased narcotics and human trafficking, migration waves, water disputes, and political instability under the Taliban — all of which have created multidimensional threats for Iran. In response, Iran has employed various measures including border security policies, regional diplomacy, and management of water resources and border livelihoods.