This chapter explores Colin Gray’s lasting impact as a strategic thinker, emphasizing his relentless pursuit of a unified theory of strategy. Gray continually refined his ideas, revisiting core strategic principles while adapting them to evolving political, technological, and military realities. He asserted that strategy follows timeless principles but demands constant reassessment to remain effective. His works highlight the critical relationship between military power and political objectives, stressing that strategists must develop their understanding through education rather than mere training. Finally, the chapter underscores Gray’s role as a dedicated advocate for strategic thinking, pushing for improved strategic practice while recognizing the inherent challenges of achieving truly masterful strategy.

This chapter challenges the conventional hierarchy between strategy and tactics, asserting that tactics play a crucial role in decision-making. It traces how strategy, once linked to battlefield manoeuvring, expands into political and business spheres while tactics become narrowly associated with execution. The chapter critiques the view that strategy sets long-term objectives while tactics focus on short-term actions, emphasising that strategy and tactics constantly shape each other. It highlights how decision-making evolves iteratively, with tactical choices influencing strategic direction in military, political, and business contexts. Finally, the chapter argues that the best strategists think tactically, recognising that success depends not only on setting objectives but also on navigating the complexities of implementation.

Growing doubts about the American commitment to European security have raised the question of whether British and French nuclear forces could ensure Ukraine's security following a US-brokered deal, and more broadly provide a nuclear shield for Europe in place of America's. Neither the United Kingdom nor France has eagerly embraced the idea of substituting its nuclear assets for those of the United States, but both acknowledge that committing their nuclear forces to collective European defence may be in the national interest, as well as Europe's interest. Nuclear strategy is all about providing a deterrent effect sufficient to avoid the most dire scenarios. Existing doctrine allows both the UK and France to claim some deterrent effect on behalf of all their European allies, and available forces - which are operationally independent of the US - enable them to do so by posing a credible risk of retaliation that a Russian leader could not ignore.

Definitions of strategy reflect changes in the nature of conflict and military thought, but also the concept's use in other areas of human affairs such as business and politics. This has led to more capacious definitions that are theoretically empty but practically useful. Joshua Rovner offers a potentially more productive conceptual schema, distinguishing between strategy as a theory of victory, and grand strategy as a theory of security. Its value, however, lies in highlighting rather than resolving the tension between military and political spheres. The symptoms of this 'strategy gap' are often poor coordination, institutional divisions, and flawed execution.

Both the Russian Federation and the United States and its allies have avoided taking actions carrying the greatest risk of escalation to nuclear-weapons use. Left uncertain is whether specific contingencies might yet prompt nuclear use. But the Russo-Ukrainian war has now been going on long enough to ground the debate in what has been said and done during its course. Russian nuclear decision-making requires the most attention, and Russian President Vladimir Putin's statements about it have been the most authoritative. He has defined Russia's nuclear red line consistently and relatively restrictively, reserving the threat of nuclear use for an existential threat to the state. He has focused on deterring the West from fighting alongside Ukraine, disregarding those who wanted to punish the West for the support it was providing. So long as NATO continues to respect Putin's red line, there is no reason to believe Putin would authorise nuclear use.

Until the Russian invasion of Ukraine, there was little evidence of what a conventional war between the regular forces of peer competitors might look like today. After the total war of the twentieth century, the evolution of precision-guided munitions and drones set up the possibility of a new ideal type of conflict, in which U.S.-NATO coalitions could quickly defeat the regular forces of much weaker opponents, largely from a distance, while avoiding excess loss of civilian life. "Smart" weapons created the perception that when civilians were killed, this was an operational failure. Russia's approach to war, however, has not put a high priority on avoiding civilian casualties, but has shown that precise weapons could be used deliberately to target civilian infrastructure in ruthless and coercive air campaigns. In this essay, I suggest that the Russia-Ukraine War provides insight into what a major power war would look like. I contrast the two distinct approaches represented by Ukraine, strengthened by NATO weapons and informed by its concepts, and Russia, with its readiness to attack civil society. I focus on the resulting humanitarian disaster in Ukraine, where more than one-quarter of the population has been displaced and where Ukrainians in Russian-occupied territories have reported thousands of instances of war crimes. I conclude by considering the likelihood and potential consequences of Russia's use of nuclear weapons.