The particular aspect of history which both attracts and benefits its readers is the examination of causes and the capacity, which is the reward of this study, to decide in each case the best policy to follow. Now in all political situations we must understand that the principle factor which makes for success or failure is the form of a state's constitution: it is from this source, as if from a fountainhead, that all designs and plans of action not only originate but reach their fulfillment.