Uncodified constitution

An uncodified constitution is a type of constitution where the fundamental rules often take the form of customs, usage, precedent and a variety of statutes and legal instruments. An understanding of the constitution is obtained through reading commentary by the judiciary, government committees or legal experts. In such a constitutional system, all these elements may be (or may not be) recognized by courts, legislators and the bureaucracy as binding upon government and limiting its powers. Such a framework is sometimes imprecisely called an "unwritten constitution"; however, all the elements of an uncodified constitution are typically written down in a variety of official documents, though not codified in a single document.
An uncodified constitution has the advantages of elasticity, adaptability and resilience. A significant disadvantage, however, is that controversies may arise due to different understandings of the usages and customs that form the fundamental provisions of the constitution.
A new condition or situation of government may be resolved by precedent or passing legislation. Unlike a codified constitution, there are no special procedures for making a constitutional law and it will not be inherently superior to other legislation. A country with an uncodified constitution lacks a specific moment where the principles of its government were deliberately decided. Instead, these are allowed to evolve according to the political and social forces arising throughout its history.
When viewed as a whole system, the difference between a codified and uncodified constitution is one of degree. Any codified constitution will be overlaid with supplementary legislation and customary practice after a period of time. Conversely, customs and practices that have been observed for long periods in an uncodified manner may be added to the written constitution at various junctures, such as in the case of the 2-term limit for Presidents of the United States. This custom was observed for nearly a century and a half, unbroken, without any enforcement mechanism until it was ignored by Franklin Roosevelt, after which it was added to the written Constitution as mandatory .
Current states.
The following states can be considered to have an uncodified constitution: