Granted that sovereignty suffices the existence of the act, would that also suffice its non-existence as well? If so, the problem would be that it leads to having both the existence and non-existence of the act at the same time. And if not, it would mean that the non-existence of the act must be impossible and its existence must be necessary, because non-sufficiency of sovereignty for non-existence and its sufficiency for existence damage the state of equality of existence and non-existence in the essence of the contingent and change contingency into the necessity of existence.
To interpret sovereignty as "may or may not act" is just a linguistic account that does not solve the real problem. In any case, with sovereignty the existence of the act as a contingent effect either remains possible or becomes necessary. If it remains possible, the question still remains why will it exist? Why did not contingency suffice the existence of the act in the first place? If it becomes necessary the problem with the theory of necessity would repeat.
Although the principle of impossibility of preponderance without a preponderating factor is not demonstrated and it is just self-evident, there must be a reason why something becomes self-evident. The reason here is the essential need of the contingent for a cause, that is the contingent as such is rationally impossible to exist or not to exist. The impossibility of existence and non-existence for the contingent as such is an essential judgment of our reason whose subject matter is non-necessity of existence and non-existence. This is a universal and essential judgment of the reason that has no exception like any other proved universal and absolute judgments.
What is the meaning of sufficiency in saying that the sovereignty is sufficient for the existence of a voluntary act? Our master, Sadr, uses the expression "may or may not act". If it means possibility of existence the problem is that this is something, which has been already there, and if it means necessity the problem is that this is the same idea involved in the theory of necessity.