America and the Challenge of Afghanistan: From "Limited War" to "Principled Realism" (2001-2019)

The 9/11 incident, along with all the implications for the US security strategy, tested the scope of US commitment to South Asia, and in particular to Afghanistan. The military invasion to this country in the first weeks after the 9/11 incident gradually outlined a broad agenda for mobilizing hard and soft resources for US leaders and each one of these leaders followed a specific behavioral pattern, based on Afghanistan's peripheral and domestic conditions, US domestic conditions and their own individual belief systems. The main question of this article is: What are the similarities and differences of US foreign policy with regard to Afghanistan during the Bush, Obama, and Trump presidencies? In response to this question, the hypothesis is: US foreign policy on Afghanistan between 2001 and 2019 was focused on counterterrorism and the relative maintenance and strengthening of the central government. However, in the Bush era, an extra-regional approach (Iraq-Afghanistan-based), in the years of Obama's leadership, the intra-regional approach (Afghanistan -Pakistan) and the in the Trump era a principled realism approach was followed. The Method of Research is Comprative Study.