The Formal Character of Preambles and the Political

What is the formal character and which is the political relevance of a preamble? It is widely understood that preambles deserve maximum attention, as their content reveals definitions, objectives and core values of the constitutional orders involved. My opinion, however, goes the other way. I argue that it is, instead, because of the form – because of their formal nature- that preambles are essential constitutional pieces. At least it looks like this for those of us who foster a theoretical-political outlook toward the Pouvoir Constituant's decision making process.
In short, the existence, connection, and justification of the Constitution, the State and the derived legal order, are precisely the epitome of the preamble´s formal character. The conceptual and the practical implications of such category is also another profile that will be developed and brought to discussion by the panel.