The central thrust of the argument could be boiled down to "give war (or coercive policing) a chance" — challenging the notion that state formation and the maintenance of a state monopoly of effective violence can be effectively accomplished without resort to coercion. At the same time, this coercion is generally most effective at maintaining (once established) the state monopoly of force when it is exercised with a degree of sophistication and discretion, which may ultimately require a move away from patrimonialism and a surrender of some privileges or benefits to non-elite interest groups. There is some discussion of military structures but the primary focus of the book is on the creation and use of various types of police services, militias, secret police, and gendarmeries.
As in Giustozzi's book on Afghan warlords Ismail Khan and Abdul Rashid Dostum Empires of Mud, the volume aims to put the reader in the perspective of state-building elites who must contend for power with insurgent movements or rival elites at the national and sub-national level. The book argues that these elites' frequent decision not to embrace institutional, rules-bound techniques of policing or other reform measures is generally informed by rational survival strategies that take into account the political, security, and resources constraints they operate under, and that misdiagnosis of these constraints generally leads to failure. The longest single chapter elaborates at length on the misdiagnoses and perverse incentives created by external interventions into local conflicts and political systems, even (especially) when conducted under the guise of modernizing reform.
I'm rounding up on my review - 3.75 stars might be closer, as the book is good but not perfect, and this material may be covered better in other volumes. Giustozzi has become a very prolific author in recent years, and I hold his analysis in high regard; this book appears to have been generated through primary research he conducted for other works and subsequently turned into a published volume, which makes for a quick but sometimes incomplete read. A significant amount of literature review from a wide variety of cases was involved, but is heavily summarized due to the book's brevity. Overall, this was an interesting read and offers a useful perspective for state-building analysis.