There is no hard-and-fast decision rule or trigger mechanism to which he or she must adhere in deciding whether supply conditions in the oil market justify an intervention.
If margin rule changes for a minor commodity can trigger a general price run, imagine what would happen if a series of broad based rule changes were implemented.
Still, it should have been fairly obvious that this rule was going to trigger the inevitable firestorm, particularly when the leadership of the Catholic Church has been warning for months that they were not going to let this one go by without a fight.