Republics have adopted various measures to prevent the establishment of a self-perpetuating dynasty, by limiting public office-holding to a stated number of years; by providing that the office holder may not succeed himself. Political leaders may avoid such provisions by staying in the background, having their closest associates elected to office, and when their term is ended, secure the selection of other associates upon whose personal fidelity they can rely. All such measures require that the leader keep the favor of a considerable number of his constituents. To avoid this often difficult or disagreeable task the leader and his close associates may persuade their constituency to by-pass both constitution and parliament, enlist the support of the military, seize power and establish an arbitrary dictatorship of admirals and generals or establish a committee of military leaders who will pick out civilian office holders willing to follow the political line laid down by the military leaders. As republics gain in wealth, increase their power and broaden their geographical base by bringing outside peoples under their sway, their dependence upon military means of resolving public controversies becomes greater. This is particularly true where outsiders brought under the republic's authority have mature political institutions including their own leaders and their own ways of dealing with public relations. Given such a situation, the control by the republic over the policy-making apparatus of dependencies is likely to have been established by force of arms. In such a case it is only a matter of time and occasion when the dependency will demand the right of self-determination and be prepared to fight for independence of "foreign tyrants, oppressors and exploiters." Minor inexpensive military operations for the suppression of colonial revolt which are quickly and successfully ended may add to the stature of empire-building leaders. But major operations, long continued, expensive and inconclusive, will undermine the prestige and weaken the position of the most firmly seated imperialist. The Boer War against the British and the wars waged by the Koreans and the Vietnamese against a series of occupiers and exploiters are excellent examples of the operation of this principle. As empire building proceeds under its inescapable expansionist drive, a point will be reached at which the overhead costs of maintaining the empire will exceed the income. As that point is approached in one after another of the empires comprising the civilization, the central authority will be successfully challenged by the dependent, colonial periphery. Ordinarily, such challenges will coincide with the inter-imperial wars which have periodically disrupted every civilization known to history. When such a coincidence does occur, as it did in western civilization from 1914 to 1945, the bell is likely to toll loudly for the civilization in question.