MACKINDER was, by training and profession, a geographer--a geographer who, by reflecting more deeply than his colleagues on the conclusions to be drawn from his special knowledge, became a strategist with counsels of value for general staffs and, through them, for statesmen. But he was not a constructive political thinker. Nor indeed did he ever claim to be one. So far as public affairs were concerned, he regarded it as his duty to keep his fellow countrymen and the peoples of the English-speaking world constantly aware of what he called the "realities" of world politics, stark realities underlying practical politics of any kind, democratic or otherwise. The primary purpose of political activity, he always maintained, as Aristotle had maintained before him, was to ensure life--the survival of the citizens and the state or community to which they belonged. Only after that had been ensured was it legitimate for public men to spend time and thought on the organization of the "good life," that is to say, on arrangements in which the survival 4' the state' could be taken for granted.
In the days when Mackinder was setting forth these views at Oxford, in the first decade of the century, nothing seemed less likely to the young men who listened to him than that their careers would be set in an age in which the civilization they had inherited from the Victorian era would be sharply challenged and the very continuance of ordered life in the small island of Great Britain placed in jeopardy. He himself lived to see the cloud, which he had discerned when it was no bigger than a man's hand, darkening the whole planet, but he had passed away before the gravest threat to the survival of our civilization--the acquisition by the rulers of the Heartland of control over the instruments of atomic power--had become a grim and ever-present reality for the responsible statesmen and peoples of the free world.