What sources of international law govern the issue of diplomatic immunity?

Question

What sources of international law govern the issue of diplomatic immunity?

Answer 1

Customs and traditions are the sources of diplomatic immunity because it has been a long practice of countries that diplomats are not subject to the laws of other countries.

Answer 2

Diplomatic immunity protects the international channels of diplomatic communication by exempting diplomats from host country jurisdiction so that the diplomats can perform their duties with freedom, independence, and security.  

The source of immunity is based on international treaties and signatory reciprocity.  Under the concept of reciprocity, diplomats assigned to any signatory country in the world benefit equally.

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