Prudence and the estate tax

Rob asks whether anyone will "dissent" from his view that "the existence of the estate tax -- putting aside questions of rate, when it kicks in, etc. -- is supported by CST, and perhaps more strongly, that its elimination would be condemned by CST[.]" 

I would not term my thoughts here a "dissent" but, I have to admit, I am not sure how to "put aside questions of rate, when it kicks in, etc." because, it seems to me, such questions are inseparable from an effort to apply the principles of CST to the issue at hand. 

Does CST require a regime under which -- in addition to sales taxes, property taxes, progressive income taxes, capital-gains taxes, gift taxes, etc., all in the service of the common good -- all estates of more than $1 million are subject to an additional tax of (say) 50%?  Of course not.  Would a movement -- defended in good faith in terms of overall economic benefits to the nation -- from such a regime to one where the tax rate was reduced to 45%, and the tax kicked in at $2 million, clearly be inconsistent with principles of CST?  Of course not.  Would the elimination of the estate tax altogether, as part of a comprehensive package of tax reforms and increases that, taken as a whole, increased productivity and government revenues, which were then -- we can dream -- conscientiously directed toward the common good, in accord with subsidiarity, the preferential option for the poor, and so on, clearly violate principles of CST?  (I am not saying, of course, that I have any idea what such a package would look like).  Not necessarily. 

Now, Rob asks about this proposal:

Let's assume, for the sake of argument, that the estate tax were to apply only to estates of $100 million or more, and that its rate was 5%.  At these numbers, it is difficult to discern significant incentive-based consequences in terms of wealth creation and productive behavior.  There would still be calls for its elimination, of course, but they would run along the lines of "It's mine -- hands off!"  Such bright-line principles, lacking a functional justification relating to the common good (or the option for the poor, solidarity, etc.) appear to me to be directly opposed by CST.

I suppose I share Rob's instinct about such a proposal.  On the other hand, I wouldn't think it fetishizes private-property rights to say that it is not the case -- is it? -- that one's right to lawfully acquired property dissolves whenever the public authority asserts a need that might be served by taking that property.  And, it seems to me that it would be reasonable, when assessing Rob's proposal under CST principles, to ask whether the (minimal) funds raised through such a tax actually would be used to promote the common good.  What if, for example, the funds were ear-marked for embryonic stem-cell research?

Now, I'm sure that Rob is right and that, in fact, much of the opposition to the estate tax proceeds simply from an excessive enthusiasm for the "hands off!  It's mine!" principle.  (I'm also sure that much of the support for the estate tax has little to do with the common good, and reflects instead pandering to the "soak the rich!" instinct.)  Still, I continue to think that, with respect to most policy questions relating to taxation, regulation, and spending that are likely actually to be presented, CST provides principles that we are bound to employ, but not bright-line answers.

School choice, of course, is the exception.  There, the answer is clear.  "On this issue, there is no debate."  =-)