The Effect of Failure by a Third Person on Vendor's Exemption from Liability (A Comparative Study under Vienna International Sale of Goods Convention 1980 and Iranian Law)

According to the second paragraph of Article 79 of the Vienna Convention of 1980, if the party's failure is due to the failure by a third person whom he has engaged to perform the whole or a part of the contract, that party is exempt from liability only if: he is exempt under the preceding paragraph and the person whom he has so engaged would be so exempt if the provisions of that paragraph were applied to him. The controversial issue of this Article, on the one hand, is the conditions that a person involved in a deal should have in order to be considered as a third person as mentioned in the second paragraph of Article 79, and whether general suppliers are regarded as third person or not. On the other hand, the question is whether the imposition of certain rule of second paragraph of Article 79 and necessity of double Force Majeure, are essential? It seems that regardless of narrow interpretation in favor of exporting, such regulation increases the obstacles of seller exemption and consequently, decreases the examples of exemption of seller for the third person actions before the buyer. In Iranian law, if the non-performance is Force Majeure to the seller according to the general rule, the seller can use it as an excuse before the buyer; Even if non-performance of the third person, is not actually caused by Force Majeure.