Consider two countries, X and Y.
X and Y sign an agreement. X unilaterally pulls out of the agreement at will, then attacks Y through the imposition of sanctions. Y insists on complying with the original agreement.
X then imposes secondary sanctions on any countries that do business with Y. Y insists on complying with the original agreement.
Time passes. X attacks Y again with more sanctions. The sanctions begin to take their toll. Y still complies with the original agreement.
Eventually, Y, the weaker party, decides to attack a third party, Z, which X had (unilaterally) pledged to defend. Y’s rationale: in attacking this third party, Y pulls X into a conflict where it, Y, enjoys a certain advantage that it doesn’t enjoy in a direct, frontal attack on X, which Y cannot win. The attack creates physical damage but no human casualties.
Paradoxically, Z itself expresses skepticism that Y is responsible for the attack on it, but let’s assume that Z is wrong, and that Y really is responsible for the attack.
X then threatens full-scale war against Y. Y promises to respond in kind, then announces its intention to breach the agreement.
Incidentally, the dispute as a whole concerns X’s fears about Y’s coming to possess weapons that X has possessed for almost 75 years, that its allies have had for decades, and which neither X nor its allies ever intend to relinquish. It is simply an axiom of X’s foreign policy that some countries are better than others, and that different moral standards apply differentially to different kinds of countries; good countries are allowed to have the relevant weapons, bad countries are not. X remains a good country despite its unilateral violation of the agreement with Y, and Y remains a bad country despite its compliance with that agreement. X’s intrinsic goodness nullifies any obligation to adhere to the agreements it signs with Y; Y’s intrinsic badness remains unaffected by its adherence to the same agreement, no matter how scrupulous.
Question: who is the aggressor in this scenario?