First, to develop a better intellectual understanding of one or more other systems. For purpose, the challenges include time, the need to develop expertise, language barriers, and the need to understand the broader context- both legal and social- in order to develop that expertise.
Second, to enhance one’s capacity for self-reflection on one’s system, in order to develop a better understanding of it. Deciding what are true and what are false necessities is quite a challenge. Determining what are true and false necessities may turn out to be very complicated indeed; so we need to add this at the list of challenges.
Third, beyond self-reflection to understanding your own system, aims at reflection to develop a better understanding of what are the normatively preferable best practices.
Fourth, sometimes we study comparative constitutional law because domestic constitutional doctrine or constitutional texts asks a question that is comparative in nature.
In deciding whether and when to use comparative materials in constitutional interpretation, at least three kind of factors are relevant.
the nature of the domestic issue
for judges, the nature of the transnational source will affects its relevance
judges need to consider the comparability of contexts
Three possibly distinctive challenges in comparative constitutional law:
Complexity of the historical context and the interdependence of constitutional provisions
The tendency in constitutional law and theory to conflate the normative and positive
The expressivist aspect of constitutional law
Some constitutional preambles say something like; “We the people...” It claims about identity and self-expression. The point here is the degree to which the expressive components of constitutions may complicate our efforts to do comparative analysis at the functional level.
