Many of us have grown used to conservative rationalization about liberal activism, as an attack to defend their interpretation of the constitution. We have also grown accustomed to the pronouncements that conservative beliefs are such that the constitution must nr subjected to the original intent of the originators. Therefore, the meaning must not change.
There are a few problems with that, starting with the fact that the founders built specific mechanisms into the constitution to facilitate its update. If the constitution was intended to remain unchanged, why include an amendment process?
Much of the constitution was constructed by James Madison. It was guided by discussion and debate with other founders. Significant issues were debated in the Federalists Papers, with Alexander Hamilton providing numerous opposing views, alternative opinions or laying out political theory. However, much of Madison's guidance also came from Jefferson's input.
But there's really no need to speculate on that because Jefferson himself states exactly why it's important to change the constitution. In his own words:
When an instrument admits two constructions, the one safe, the other dangerous, the one precise, the other indefinite, I prefer that which is safe and precise. I had rather ask an enlargement of power from the nation, where it is found necessary, than to assume it by a construction which would make our powers boundless. Our peculiar security is in the possession of a written constitution. Let us not make it a blank paper by construction. I say the same as to the opinion of those who consider the grant of the treaty-making power as boundless. If it is, then we have no constitution. If it has bounds, they can be no others than the definitions of the powers which that instrument gives. It specifies and delineates the operations permitted to the federal government, and gives all the powers necessary to carry these into execution. Whatever of these enumerated objects is proper for a law, Congress may make the law; whatever is proper to be executed by way of a treaty, the President and Senate may enter into the treaty; whatever is to be done by a judicial sentence, the judges may pass the sentence. Nothing is more likely than that their enumeration of powers is defective. This is the ordinary case of all human works. Let us go on then perfecting it, by adding, by way of amendment to the constitution, those powers which time and trial show are still wanting. But it has been taken too much for granted, that by this rigorous construction the treaty power would be reduced to nothing. I had occasion once to examine its effect on the French treaty, made by the old Congress, and found that out of thirty odd articles which that contained, there were one, two, or three only, which could not now be stipulated under our present constitution. I confess, then, I think it important, in the present case, to set an example against broad construction, by appealing for new power to the people. [Emphasis added.]
Jefferson clearly states that the constitution is an imperfect, and that in its enumeration things have been missed or will come to be. Thus Jefferson favored amending the constitution to address issues as they arose, rather than permitting it to diminish into a virtually irrelevant document subject to uncertainty and ambiguity.
So it appears that liberal activist interpretation of history, the constitution and reading of "original intent" is actually most accurate. If conservatives were true originalists they would know that the document is anything but dead.
But if conservatives have a better understanding than the founders themselves that's fascinating.