Final answer:
Substantive law is distinguished from other forms of law by its focus on defining rights, duties, and liabilities, separating it from procedural law, which outlines legal processes.
Step-by-step explanation:
The attribute that distinguishes substantive law from other forms of law is that it defines rights, duties, and liabilities. Substantive laws are the set of laws that governs how people behave and are concerned with the substance of the law. For instance, it dictates what actions are considered crimes, as well as the rights of individuals and the legal responsibilities they owe to others. In contrast, procedural law outlines the methods and means by which substantive law is made and administered. In the context of international relations, international law establishes the rights and obligations of states by a compliance mechanism through treaties and customary practices.