A seasoned scholar, strategist, and expert in space policy and strategy, Dr. John J. Klein is well-versed in applying strategic theory to the space domain. In his new book, Fight for the Final Frontier: Irregular Warfare in Space (2023), Klein argues that irregular warfare, in both its military and nonmilitary forms, is a vital and underutilized concept for understanding malicious activities in space and the nature of space warfare. His argument draws on a diverse list of strategic theorists, historians, and contemporary policy analyses. Klein weaves these sources together persuasively, providing an accessible overview of a technologically demanding subject. Policy generalists and students, along with veteran analysts of space policy, will benefit from his account.

Klein shows that irregular warfare theory is crucial for understanding warfare in space. Defining irregular warfare as “conflict apart from major, conventional wars,” (7) Klein states that irregular warfare serves political aims, includes both state and non-state actors, and involves the use of force during armed conflict and actions below the threshold of armed conflict. Irregular warfare and competition are not new phenomena, and they have always functioned according to the general ‘lore of war.’ Irregular warfare may be preferred for two reasons: 1) irregular actions often are seen as occurring below the threshold of armed conflict and 2) irregular actions may be the only available way to achieve strategic aims. Malicious activity below the threshold of an armed response tends to severely hinder nation-states’ ability to invoke defense agreements, mutual response, or self-defense—delaying or preventing a military response. Finally, irregular actions may achieve outsized results with less effort and may be preferable depending upon the strategic context.

Klein demonstrates that the benefits of irregular warfare are clearly heightened in the space domain. Space assets are often proverbial sitting ducks, and actions in space are perceived as less severe. Satellites may be damaged reversibly or interfered with through nonkinetic means. Attributing irregular actions is often more difficult, analogous to malicious activity in the cyber domain. Over time, the use of irregular actions may create significant friction and achieve strategic effects. Strategic lasing, radio-frequency jamming, and cyberattacks on key infrastructure, for instance, can produce an outsized effect. For smaller space faring nations and actors, a conventional military force in space simply may not be viable or desirable. Recent examples of space warfare, including the Russian cyberattack on the U.S. satellite company Viasat, support Klein’s assertions. In short, the space domain is likely to be subject to protracted, irregular actions that achieve strategic effect over time.

Klein offers particularly useful insights into the tactics, techniques, and indirect effects of irregular space warfare. He also provides a nuanced analysis of activities that fall below the threshold of armed conflict. His examination of small space wars, Fabian strategy, maneuver warfare, gunboat diplomacy, and the potential role of a space ‘fleet in being’ demonstrates creative application of strategic thinking and robust use of relevant analogy. While his sections on cyberattacks and jamming, lasing, and electromagnetic attacks are informative, an eager reader could have benefitted from further elaboration. Specifically, Klein could have provided more in-depth analysis of the 2022 Viasat hack as a beneficial case study. Given its claim of the remarkable similarities between the cyberspace and space domains, the text could have integrated additional research on strategic cybersecurity approaches and provided more detailed information on cyberattacks on space assets as a tool of statecraft.

Later in the book, Klein unpacks lawfare as a means to achieve competitive advantage in space and the roles of commercial entities, privateers, and space pirates within the space domain. Reconstructing these subjects generally and within the context of space, Klein solidly integrates them into his overarching conceptual framework, elucidating their significance as integral parts of a cumulative space strategy. Chapter 7’s discussion on the exploitation of emerging space technologies to achieve an asymmetric advantage and the implications of their dual-use nature is insightful—and it rightfully argues against over-hyping technology and the importance of innovation. Finally, the book’s concluding chapter offers useful guidance in avoiding strategic pitfalls and achieving U.S. space strategy’s primary aims.

While the book makes many of its assumptions explicit, it may have benefitted from more thoughtful reconstructions of counter-arguments. Klein declares, for example, that “it is worth acknowledging the inevitability, however regrettable, of armed conflict in space” and dissects why he believes this to be the case (46). Not everyone agrees. Dr. Joan Johnson-Freese, for example, calls into question the inevitability of space warfare in her own book on 21st century space warfare. A response to Johnson-Freese, one of the leading analysts of national security and space policy, would be illuminating. Similarly, his argument against treating space as a “global commons” would be stronger if he engaged more substantively with scholars who use that metaphor.

Overall, Klein equips strategists with the necessary background to ensure strategic space access and to counter irregular warfare in space. The book is well-written, rich in theory, and well-sourced. Readers will learn a great deal from Klein’s overview of the many issues associated with space policy and irregular warfare. Indeed, one gets the impression that each chapter, even sub-sections, could in themselves constitute entire books. Fight for the Final Frontier may prod scholars to start writing.