The issue arises when we force other countries not to sell to said sanctioned country (this case being Iran) with the threat of sanctions towards them should they violate our bullyish whims, which everytime we get on the subject of sanctions you conveniently leave out. The analogy with the car salesman quickly falls apart as well when we determine that we aren't talking about cars and other petty materialistic shit but necessities such as medicine, oil, food etc. We can argue semantics all day long on whether sanctions are or are not an act of war. When it all boils down would you concede that sanctions are aggressive, that they stregthen the internal power structure of said sanctioned country by way of a sense of obligatory nationalism, that they effect the poorer citizenry a hell of a lot more than the leaders of said sanctioned countries, that they breed hatred towards the United States, that they often times lead to war, and that they are foolish in terms of a far sighted peaceful foreign policy approach? Because if we can agree on those simple facts, then the issue of whether or not they are an act of war becomes moot.