I must respectfully take exception to your assertions, my friend.  The very purpose of reducing the Constitution to writing was to specifically set forth and define the powers and limitations of the federal government.  Who better than Madison to articulate what he meant when he helped to craft those words?  I simply cannot accept any shade of the notion that the US Constitution is as malleable and arbitrary as you claim, Supreme Court rulings notwithstanding.  Courts can and do err in such rulings.  A classic example of one such ruling is the one by Judge Jeffrey Spinner in IndyMac Bank v. Yano-Horoski, as recently cited in Robert Franco's Source of Title Blog.

My argument is simply that if the Constitution can be interpreted to mean "anything", then it will eventually mean "nothing".  It says what it says, and if we as citizens wish to change it, there is a process for doing so.

Regards,
Scott Perry