Interpretation of constitutional doctrines uses both lex scripta (the written law) and lex non scripta (the non-written).
While the written may not always be easy to discern at least it is right there in front of you. The opportunity is available to all, to go and read the Constitution. There may be a difference of opinions as to what it means, but at least it is right there to be read. Then an individual is able to form his or her own opinion about the meaning of the language.
That is not as easy to do with the non-written law. To understand the non-written rules an individual must scour through court opinions. The opinions often contain doctrinal vernacular specific to constitutional analysis. Courts may define the doctrinal theories or standards they are using, but do not always. Furthermore, sometimes the definition is provided and used, but it is not referred to by name. This can lead to confusion of those who do not have a background in constitutional law.
Areas of constitutional law: