Space Warfare: Strategy, Principles, and Policy, 2nd ed.

Space Warfare: Strategy, Principles, and Policy, 2nd ed. by John J. Klein. Routledge, 2024, 300 pp.

With the increasing focus on and discussion of space warfare and space strategy, it makes sense that John Klein’s update to his 2006 Space Warfare is not only brought up to date but also significantly expanded. With 50 percent new content—by Klein’s own accounting—the second edition almost warrants being called an entirely new book rather than an update.

Growing from his original 2004 article, “Corbett in Orbit,” Space Warfare’s main premise is that there is much that can be applied in thinking about spacepower from the maritime thinking of Julian Corbett in particular.¹ In doing so, Klein not only makes the case that a maritime analogy—despite the differences between the maritime and space domains—is appropriate to use but also develops several strategic principles from Corbett’s work that he sees applicable in space. These include ideas such as the idea of celestial lines of communication (CLOC), the importance of dispersal in space, and the potential primacy of the defense in space. In the years since Space Warfare was initially published, Klein’s book has become one of a handful of works that have been seen as constituting the core of spacepower theory.

Largely following the footprint of the first edition, Space Warfare is divided into three parts: an introduction, strategic principles, and comparisons and recommendations. The first section includes an introductory chapter, a chapter on contemporary strategic frameworks that may be useful analogies for space, and a chapter summarizing Corbett’s major strategic principles from which Klein’s ideas emerge.

Of note is an updated chapter two that engages with more recent spacepower theory, most prominently that of Bleddyn Bowen.² It is from an examination of Bowen’s cosmic coastline that Klein launches into a brief discussion of brown-water and blue-water thinking as it regards space, touching on a major question currently being debated in the space community. Reflective of the rest of the book, Klein—rather than picking a side—argues that choices about whether space is a supporting or supported element present a false dichotomy, and instead looks at the issue holistically. This dualism is heavily present throughout the book, demonstrating the ways in which Klein has matured as a spacepower thinker.

The second section represents the meat of the book with 11 chapters, each focusing on one of Klein’s strategic principles. While each of these chapters is substantially updated, two chapters are of particular note. First, chapter 10 on blocking celestial lines of communication once again reflects a more nuanced approach. Further subdividing the kinds of close and distant blocking, he provides additional distinctions with close and distant blocking of both physical communications and the electromagnetic and network spectrums.

Second, Klein’s chapter on space as a barrier in his first edition is much enlarged in this edition. “Limited Space Warfare, Asymmetric Advantage, and Coercion” begins with a new element drawn from Corbett—that of a disposal space force. Referencing the idea that “satellites don’t have mothers,” he argues that a small space force might be of limited use to fulfill limited means, even if it is destroyed in the process. While it is certainly true that loss of life may be contained, one question left unanswered is what effect the debris created in such a scenario might have after the conflict. In unlimited conflict, this might not be an issue, but in a limited conflict as Klein describes, there may be a question as to the strategic utility of creating a situation that may be a Pyrrhic victory.

The final section contains two chapters, a new one comparing the strategic principles of the book to space doctrines currently being considered or used and a final one considering the future of space policy and strategy. It is perhaps unsurprising that many of the same policy recommendations present in the first edition remain, including calls to “very slowly” develop and deploy space weapons (261). What is welcome is the far longer discussion of these ideas. New to the list of suggestions is also an important one in an era when discussion of single countries seems to dominate the foreign policy discourse, specifically that “policymakers and military leaders must fight the urge to take a preexisting and well-balanced military organization and specialize it against one kind of foe, within one particular domain, as part of one potential future” (264).

Having read and used Klein’s work over the years, this author finds the second edition of Space Warfare reflects a much more sophisticated and nuanced style of thinking and analysis. In addition to the significant expansions, it includes greater development of topics that have been covered in some of his more recent works, including last year’s Fight for the Final Frontier: Irregular Warfare in Space (Naval Institute Press, 2024). He also highlights the ways in which his previous work fell short, thus indicating how his thinking has changed. For example, Klein admits that he “erred almost 20 years ago when comparing the works of Mahan and Corbett,” stating that “there is, in fact, no need to encourage space strategists and students to identify as either ‘Mahanian’ or ‘Corbettian’ and to see the two men and their ideas in opposition to one another” (36). Instead, this more nuanced approach notes how Mahan’s and Corbett’s works play off one another and are in fact more similar than they are different. The humility shown in addressing this and other issues is refreshing.

As might be expected when updating a book as much as Klein has done here, there are points at which new elements feel shoehorned into the previously established framework of the book, making for a bit of a stilted read. This element is perhaps most clearly seen in the first chapter, which seems a bit repetitive given the discussion of significant locations in space in later chapters of the book. It is this chapter, perhaps more than any other, that might have been scrapped entirely from the previous edition and written from scratch to give this update a really fresh introduction that clearly lays out the plan of the book.

While Klein has certainly included more discussions of the commercial space industry in the second edition, there are parts of his analysis with respect to commercial space that deserve a bit more attention. For instance, Klein highlights Corbett’s argument that an adversary’s trade via lines of communication is something that in turn can be targeted to exert pressure on a state. In a similar vein, Klein later notes that economic coercion may be applied in space—assumingly through the blocking of celestial lines of communication. While Klein’s discussion rightly highlights how the global economy is largely dependent on space and space-based systems, he neglects the ways in which this global economy is largely interdependent. In other words, were a country able to successfully block an economic CLOC as Corbett/Klein suggests, it might not be able to limit the economic effect of such a thing to the targeted country.

Similarly, in a later chapter, Klein suggests that one method of blocking CLOCs would be withholding commercial satellite communications from an adversary. While there are regulations in the United States that give the government some measure of control over commercial space companies in this regard—for instance, shutter control on remote imagery satellites—no attention is given to whether similar legal provisions are in place in other countries with commercial providers or whether the commercial providers would be willing participants in such a scheme. Klein does note the increasing power of the commercial space industry, but he seems to be leaving greater consideration of such issues for the next edition.

There is no doubt that Klein’s updated Space Warfare will be of interest in the general space community and in the growing number of classrooms devoted to discussing issues of spacepower and space strategy. Though some may be hesitant to pick up a second edition, wondering whether it warrants a thorough reading, readers well acquainted with the original will certainly find enough new content here to not only hold their interest but also stimulate further discussion.

Wendy N. Whitman Cobb, PhD