The Old System based on the balance of power and self-interest couldn’t guarantee the peace, order and prosperity. Security could be guaranteed only when the nation has enough power counterattack or join with other nations to fight against the bigger power or aggressor to prevent it from becoming the dominant nation. The diplomacy conducted secretly and made military alliances with other nations to prevent from invading.
The European could not maintain peace and order with the system. The very often the war broken between the major European powerful countries, Britain declared war against France and others, France during the Napoleonic revolutions declared the war and tried to united the Europe, and when the Germany reunited it war against and controlled the vast part of Europe.
Besides declaring the wars against one other and competed for the power in their home lands, the war also broken in the colonized lands. European countries dominated the world by colonizing other countries, benefited themselves and disadvantaged the colonized countries. The European major power drawn the world into the several wars and two world wars but were not able to end the wars.