What is meant by balance of power theory in international relations?

Answer 1

Balance of power refers to the existence of more than one powerful nation existing at a time. The theory is that if you have two powerful nations countering each other, no nation will be able to impose its will on the rest of the world.

Balance of power, therefore, creates peace through constraint.

Answer 2

it's mean that the power of USA can't negotiate the poor afghan but they should with China