Complex sentence: The Loss of Strength Gradient was devised by Kenneth Boulding in 1963, who argued that the amount of a nation's military power that could be brought to bear in any part of the world depended on geographic distance.
Split into simpler sentences: The Loss of Strength Gradient was devised by Kenneth Boulding in 1963. He argued that the amount of a nation's military power that could be brought to bear in any part of the world depended on geographic distance.