Keen On

Everything old is new again in international politics. According to Jill Kastner, co-author of A Measure Short of War: A Brief History of Great Power Subversion, today's international tensions over Ukraine, Taiwan and Greenland mark a return to historical normalcy after a brief period of global American unipolarity. Kastner explains that subversion—defined as hostile or unwanted action on a rival's territory—has been a constant tool of statecraft throughout history. She presents subversion as a rational choice between diplomacy and war, where states make cost-benefit calculations about their actions. Citing historical examples from Thucydides’ Athens and Elizabeth I's England to modern-day geopolitics, she explains how nations use subversive tactics when diplomatic channels fail, but war seems too costly. Let’s hope she’s right when it comes to heading off a Chinese war over Taiwan or an American invasion of Greenland. Dr Jill Kastner is an independent scholar and historian based in London. Her work focuses