Comparison of Theory of Multiplicity of Governing Laws on Contractual Obligations in US and EU Law

In US and European Union law on contractual obligations, there is a theory called depecage. According to this theory, the parties can rule the law of more than one country while dividing the contract into different parts. There are several definitions of this theory in the writings of American and European jurists. There are questions like these: What is the exact meaning of this theory? What is the evidence for this theory in contractual obligations under US and EU law? Given that selecting the law governing the contract and the application of depecage by the parties is an agreement, what law and legal system governs the validity of the will of the parties, their competence and the form of this agreement? The present article seeks to provide a precise concept of this theory, to determine the scope of application of this theory in US and EU law in contractual obligations, and to specify the rules that the parties must follow in applying this theory in order to open a window in front of the legislator in Iranian law to approve the rule of resolving the conflict with the needs of international trade law in the field of the law governing contracts