During the early decades of the nuclear age, a debate developed on the general utility of force. In the new and dramatically altered conditions of that period, in which a third world war could have meant the obliteration of great cities and civilization, it was hard to see what political purposes could possibly be achieved by launching an aggressive war. But by the same token there were also horrendous risks in a defensive war if that required resort to the most destructive weapons available.
The dominant response, at least when it came to war among the great powers, was to argue that the role of military power would henceforth lie in its latency. This was captured most effectively by the concept of deterrence. In this respect, military power, and especially nuclear weapons, had a profoundly conservative impact, serving as a warning to a radical state of the consequences of any attempt to disrupt the status quo. The fear of war served to congeal political relations, especially in Europe.
Nevertheless, even during the prolonged period of impasse in relations between the blocs led by the U.S. and USSR, there were a great number and variety of wars that did not carry the risk of escalation to the highest, thermonuclear level. Many were directed against colonial holdouts. Others were consequences of decolonization, such as those between India and Pakistan, and Israel and the Arab world. After 1990, the breakup of the former Soviet Union and Yugoslavia resulted in a number of vicious wars, while the Middle East became progressively more turbulent. The end of colonialism did not bring peace to Africa but a succession of deadly internal conflicts. In the Asia-Pacific region the rise of China as an assertive, military power came to be watched warily by its neighbors.