There are only a few countries worldwide which retain a non-codified constitution. The states of the U.K., New Zealand and Israel are the only three modern states to use an unwritten constitution. Usually, the product of an independence struggle, revolution or a major conflict, codified constitutions provide their nation with a clearly delineated list of fundamental laws and principles collated into one document.
Clarity of Meaning
Part of the benefit of a codified constitution is its clarity of meaning. Liberal supporters of codified constitutions have praised its 'predictability.' This means that anyone subject to the constitution is fully aware of its meanings and stipulations. This clarity makes it easier for the judges who oversee the passing of new laws. A process called judicial review sees judges voting on whether new laws are constitutional or not. This protects the constitution from any new law which may compromise it.
The gathering together of all the fundamental principles and highest forms of law in one place gives the judicial system a convenient point of reference. In countries without a codified constitution, the law is made up of statutes, precedents, conventions and works of authority. This separation of different components of law can slow down the judicial process.
Entrenchment is the word used to describe the way in which a codified constitution is protected from those who would change it. Special procedures are required to amend a codified constitution, and this usually requires a 'super majority' before any such amendment is passed. This protects the fundamental principles of the constitution, for example the right to a trial before a jury that is enshrined in the bill of rights. This provides a separation of powers, limiting the amount of damage one democratic party can do to another when they gain power.
Checks and Balances
Countries without a codified constitution -- the UK for example -- have been criticised for the amount of discretionary power afforded to their ruling party and even their individual prime ministers under their current systems. Critics of un-codified constitutions have stated that the prime minister in the UK is able to force changes in law through parliament as part of an individual drive to alter the laws of the land. This would be impossible under a codified constitution where the burden of proof is placed on the government to justify any restrictions in liberties.