There's simply no need to dream up an "implied power to spend". It's covered quite nicely by the "necessary and proper" clause (#18).
No, the power to spend is not a "necessary and proper" law required to levy taxes.
Sure it is. You have to pay the tax collectors. More importantly, it's necessary and proper to implement the other powers. You can't raise an army or run the post office without the ability to spend money.
The power to tax, is the power to tax, period. That's why it doesn't say anything about spending. It does however limit that power. Government can't tax us for the hell of it, just to enrich the federal government. They can only tax us for the following broad reasons:
Pay the debts
Provide for the common defense
Provide for the general welfare
Those are constraints on the the power to tax. It doesn't say anything about spending because spending is obviously 'necessary and proper' to effect the enumerated powers.
The funny thing here is that if the government had enacted a single-payer system, which would be vastly better (and also more progressive) than Obamacare, there'd be no doubt as to its constitutionality. It would amount to simply an expansion of Medicare, whose constitutionality is long established. But this Rube Goldberg contraption does raise issues, which the Court has now begun addressing.
Maybe. Hopefully we can squeeze something of value out of the debacle, and set precedent for clear limitations on federal power.
You go back to the Constitution as if no law has been based on it since. Pub dupe idiocy.