I am not sure that I get your point. The Constitution is always under interpretation. Does that mean that it has no meaning? I don’t think so. Sometimes it is interpreted more honestly than others.
The 20th century stands now in history as testimony to the power of Man’s dishonesty. The “perverted politicians” you spoke of killed and enslaved more people during that century than at any other time in history. More people lived and died under tyrannical, oppressive governments than ever before.
Only the structure of America’s Government and the kind of people that lived under it limited the impact of that century to the wanker-isms of FDR and the like. We can thank the Founders for that, but we have a duty to defend their work, if we want to continue to live free.
Absolutely we do, I am just not sure it can be defended by itself, after all the Constitution was imposed on the people with little comment from them.