Intentionalists believe that the Constitution should be understood in the way it was understood by the Founders. Consequently, it is a fixed document with static meaning; therefore, it means today what it meant then. The only way one can properly interpret it is by studying the authorial intent of the signatories.
In contrast, progressives believe that the Constitution is to be understood as a living document, which not only allows but requires that each generation interpret the Constitution in light of current needs and changes. They argue that the meaning must be ever changing in order to keep the Constitution relevant and adaptable to the issues of the day. Therefore, the interpretations and adjudications of the Supreme Court, which are not explicitly sanctioned by the Constitution, are not only appropriate, but essential.
Thus, the question of which approach is the correct one? Well, if the latter was the desire of the Founders, then I would ask, why did they include an explicit process for amending the Constitution? For the amendment process seems glaringly superfluous if the Founders intended for the Supreme Court to change, add to, or reinterpret the Constitution according to their modern opinions regarding the need to change.
Moreover, one may even go so far as to suggest that both of the legislative houses are, if not extraneous, at least marginalized in significance since legislators were/are actually the nation’s lawmakers.
Jefferson said, “To consider the judges as the ultimate arbiters of all constitutional questions [is] a very dangerous doctrine indeed, and one which would place us under the despotism of an oligarchy.” ((Thomas Jefferson to William C. Jarvis, 1820. ME 15:277, http://www.landmarkcases.org/marbury/jefferson.html ))
