Article VI of our Constitution states that "…. This Constitution and the laws of the United States which shall be made in pursuance thereof… shall be the supreme law of the land; and the judges in every state shall be bound thereby… …The Senators and Representatives before mentioned, and the Members of the several State Legislatures, and all executive and judicial Officers both of the United States and of the several States, shall be bound by Oath …" Therefore, this above clause makes two things very clear that first the supreme law of this country is the Constitution and secondly that all three branches of the government shall be bound by this supreme law of the land.
The good news is that our Constitution doesn't equivocate, and the further good news is that our Constitution is a written document. As for those that wrote and thereby approved the Constitution by affirming their signatures to the Constitution, none of them are still alive, so alas we are stuck with the present day judiciary, the supreme court of this fine land, as the ultimate arbiters of whether law made by the legislative branch and executed by the Executive branch are, indeed, consistent law with the Constitution.
You might think that the Supreme Court of the United States would as a matter of principle, make it their life mission to know thoroughly the Constitution, the Amendments to said Constitution, as well as having an abiding interest in legal precedents previously set in conjunction with the Constitution. In point of fact, what a Supreme Court judge does, depends upon the man or woman that is wearing the robe, to which, clearly some make it their duty to study carefully the actual text of the Constitution and thereby to adhere to it, some believe that they also need to interpret the intentions of those that drafted the Constitution to help to fill in the gaps of events never foreseen at the time of the founding of our Republic, and then for some there are judicial precedents which are carefully studied in conjunction with the reading of the Constitution, which help to tie everything together.
The above probably covers the way that all members of the Supreme Court use to look at Constitutional law, one hundred years ago, of which some still look at it in this format today, and then there is the other type of activist judge which exists at the present day. Some members of today's Supreme Court, feel, that their overarching mission isn't to see the Constitution as omniscient and supreme, even though said Constitution clearly delineates means to amend it through the people and the legislature, instead, they believe since they are enlightened beings that the Constitution needs to be enlightened, updated, stretched, modernized, politicized, pulled, and so forth. No doubt, too, these special and brilliant judges can site all sorts of cases to which because of their liberal reading of our Constitution, they were able to find law that was more accommodating, more understanding, and more democratic for the people.
The problem with those that believe that we must look outside the box of Constitutional law, is that by doing so, you have, by definition, opened up a Pandora's box, to which, laws are no longer held bound by the strong arm of Constitutional fiat, but are instead liberated by the Supreme Court of the land, that has aggrandized unto itself, that foundational laws, that natural laws, that Constitutional law, and previous precedents to those laws, can be overturned by unelected judges because they decide what law is or isn't depending upon their proclivities, to which you no longer have a nation of laws, but, in fact you have a nation of unelected judges who determine what law is or isn't, effectively usurping control of this government from the people and their elected representatives into their despotic hands.