Is there a noun(phrase) for a force that upsets a given equilibrium, or creates a state of imbalance?
Iran's possession of a nuclear weapon 'will surely upset the equilibrium of power.'
I need to replace the verb phrase with a noun/noun phrase.
Iran's possession of a nuclear weapon will be a destabilising force.
The Spread of Nuclear Weapons in the Middle East: “more may be ... current unipolar structure the spread of such weapons is a major destabilising force. . . ."