How did European leaders discover that a balance of power did not decrease the chances for or among them?

European leaders discovered that a balance of power did not necessarily decrease the chances for conflict through various wars and diplomatic failures. Despite efforts to maintain equilibrium among nations, the competitive nature of states often led to alliances that escalated tensions rather than mitigated them. Historical events, such as the World Wars, illustrated that power struggles could intensify rather than diminish under a rigid balance of power framework, prompting leaders to reconsider their diplomatic strategies. Consequently, they began to explore collective security and international cooperation as alternatives to prevent large-scale conflicts.