Winning the war doesn’t always mean winning the post-war peace. Sometimes, wartime leaders make strategic decisions that are helpful in the pursuit of a battle victory but lead to bigger and longer-term security problems once the war is over. Often, they confuse strategy (a theory of victory) with grand strategy (a theory of security). Why is this the case?

SIS Professor Joshua Rovner’s new book Strategy and Grand Strategy uses historical examples like Britain and France in the American Revolution and the US during the Cold War to explore the differences between the two concepts and their implications for war and peace. To learn more, we asked Rovner some questions about what strategy and grand strategy mean for potential wars in the new Trump era, how emerging technologies are changing countries’ strategies and grand strategies, and what’s next for his research.

What is the difference between strategy and grand strategy?

Strategy is a theory of victory. Grand strategy is a theory of security. Strategy answers questions about how to fight and win a war; grand strategy answers questions about how to maintain security. These concepts should be mutually reinforcing; judicious grand strategies should put the state in the best position to win in war, and victory should leave the state more secure in the aftermath. But this is not always the case. States can fight well in the service of a deeply flawed grand strategy. In other cases, states can ruin an excellent grand strategy through wartime blunders. 

What historical or recent examples can you point to that illustrate how the two concepts interact?

Sometimes the interaction is strange and unsettling. Strategic success, for example, can leave the state worse off in terms of grand strategy. French strategy in the American War of Independence was exceptional, but the consequences were disastrous for grand strategy. The cost of fighting deepened France's financial burden at a time when it lacked the tools to manage its growing debt, a problem that led to catastrophic social and political upheaval in the French Revolution. Great Britain's wartime strategy, by contrast, was a dismal failure. But losing was good news for grand strategy because it forced British leaders to have a hard conversation about the real sources of national security. Losing the war meant Britain no longer had to garrison the colonies, allowing it to focus on its navy. This set the stage for a remarkable century of British power.  

What implications does this have for war and peace in today’s world, especially with the new Trump administration?

Ambiguous grand strategies lead to hedging wartime strategies. This was a problem for the United States in Vietnam, where it fought in the absence of a clear grand strategic concept. The Johnson administration tried many different strategies, appeasing everyone without settling on a clear approach, and the result was universal frustration. Today we have President Trump, who prefers a "transactional" style of grand strategy. Trump revels in uncertainty because he believes that it gives him bargaining leverage in peacetime. But trouble may come if the United States goes to war. 

You have a chapter on emerging technologies—how are strategy and grand strategy evolving in this age of new technology?

Historically, emerging technologies produce a regular pattern of responses. Leaders initially hope that mastering these new tools will pay off in terms of strategy by delivering quick and decisive victories. They also believe that mastery will mean grand strategic success because new technology promises big advantages in relative power. But they also worry that rival states will beat them to the punch, leaving them at risk during war and peace. Over time, however, leaders learn the limits of new technologies and become resigned to outcomes that are much less decisive. We have seen this pattern of hope, fear, and resignation in cases of naval and airpower revolutions. We are currently seeing it play out with respect to cyberspace and AI, where hope and fear are rampant. But we have not reached the point of resignation. 

What further questions did this book leave you with that you’d like to focus your research on next?

Much of the book focuses on failures. These include cases in which leaders confuse strategy and grand strategy, and cases in which strategy and grand strategy come apart. I would like to know more about the causes of success. A related question is how states make the most of strategic failure. Great Britain learned the right lessons from losing, but this is not always the case. Indeed, postwar inquiries are often contentious and unproductive. Some states lose well, and others lose badly. I would like to know why. This is particularly important for the United States, which is currently wrestling with the lessons of two frustrating wars.