It was, but, I still believe what I believe. A living document is something which helps with the times. How can the rules of men who lived over 200 years ago still apply to us without a bit twisting. We have so many things that they wouldn't have know about. Without the notion of a living document, it's hard to apply the laws, and write them. Social Security and Medicare, are they mentioned in the constitution. No, but with some interpretation, you can find the rational for them.
The tax and spending power is right there in the Constitution. That one was easy. 
Doesn't the purpose of the spending have to fall within enumerated powers?
No, not really, as opposed to regulations, the spending power is close to an unlimited power is my recollection. SCOTUS has held that in certain situations, withholding funds to a state to influence the state's policies, that the Feds cannot directly dictate, can be deemed unduly "coercive."
