the balance of power
The various magnitudes of power and authority being exerted simultaneously between multiple opposing people, groups, or bodies. With the party's huge sweep in the last election, the balance of power has been dramatically shifted in Washington. If they're able to build a functioning nuclear arsenal, the world's existing balance of power could be in danger.
the balance of power
the situation where the power held by one governing body or adversary is balanced by the power of another. The balance of power was threatened when China captured our airplane.