Mara E. Karlin in her book, Building Militaries in Fragile States: Challenges for the United States, investigates when, why and under what circumstances, US efforts to build partner militaries for internal defence succeeded and also offers some suggestions for improvement. The efforts examined include key decisions, programme execution and the nature of the US involvement with the partner state. She criticises US military interventions in what she calls ‘fragile states’ as unsustainable, thinly successful so far and fundamentally flawed.