In the last half of the twentieth century, the world's two most powerful nations, the United States and the Soviet Union, have been unable to impose their will on far smaller and weaker countries-notably Vietnam and Afghanistan-by means of armed force. Evan Luard suggests that these failures are symptomatic of a fundamental change in world politics. The conflicts in question were typical of the wars that occur today. They were not traditional set-piece confrontations between industrially developed powers, each deploying its maximum capabilities against the other as in the Second World War; they were low-level conflicts in developing countries, undertaken primarily by guerrilla forces. In all such wars the fundamental issue is political power, and the author contends that political rather than military factors are ultimately decisive. Given the declining credibility of a resort to nuclear weapons, the balance of nuclear power is increasingly irrelevant in world politics. Luard draws his conclusions from a wealth of examples in recent history. He examines the various forms of armed intervention that have taken place. He also considers how the superpowers could reduce the dangers of regional conflicts, how Western Europe could influence relations among the superpowers, and how the UN might be made more effective in maintaining peace. The book is thus a source of practical ways to defuse tension at the world's political flashpoints, and a wide-ranging survey of many of the principal issues in contemporary international relations.