唐天宝时期，边将边兵问题突出，拥兵自重的节度使已表现出威胁朝廷的倾向。李林甫通过巧妙的人事安排，确立了朝廷居中调节、北方节度使互相制约的制衡秩序，意图在错综复杂的人际关系网中化解各方冲突，使各方势力都置于朝廷的掌控之下。杨国忠入朝培植壮大了剑南节度使的实力，新势力的加入打破了既有的各方势力的平衡状态。杨国忠继李林甫为相后，各节度使必须以剑南节度使为核心建立新的制衡秩序。在杨国忠拉拢哥舒翰压制安禄山的过程中，北方节度使分化为东西对立的两大军事集团，激烈的军事竞争使朝廷对北方节度使失去了控制力。安禄山叛乱标志着天宝时期各节度使制衡关系的彻底破坏。

Jiedushi, maintaining a massive armed force, had showed a tendency of threatening the imperial court early in Tianbao period in Tang Dynasty. Intending to resolve the conflict, Li Linfu balanced the imperial court and the Jiedushi on the north border via delicate arrangements, so that different forces could be under complete control of the imperial court by complicated personal ties. The promotion of Yang Guozhong disturbed the balance with the strengthening force of Jiannan Jiedushi, even a new Jiannan-centered balance order needed to be established after the death of Li Linfu. In the process of Yang Guozhong’s allying with Geshu Han against An Lushan, the Jiedushi on the north border divided into two power blocs which confronted each other violently, no longer controlled by the imperial court. The rebellion of An Lushan was a symbol of the destruction of the balance.