This goes back to the entire notion of an income tax, and the notion of "economic gain".
I spelled this out earlier in the thread, but re-visiting it seems relevant.
If I buy a loaf a bread from the baker, she pays income tax on the profit she makes from that bread, and all the other goods he sells. She takes what is left, then decides to buy a new oven. She gives money to an oven manufacturer, who presumedly makes a profit from that sale.
Should then the oven manufacturer not be taxed on its profit, because technically, the bakers profits were already taxed?
Or should then the manufacturer be taxed on its profits, on the theory that its income is seperate from the baker's?
To be honest, there is also an element of "screw the rich" in the estate tax.
I will present some of Teddy Roosevelt's speeches at the time when he was arguing for such a tax:
http://www.tax.org/Museum/1901-1932.htm
I don't entirely disagree with that.
I think that at some point we have to ask ourselves, does one human being really *need* to have billions of dollars?
Is the ac ulation of vast wealth even moral?
I don't think so. You can't take it with you, and you do your children no favors in giving them something they have usually done little to earn.
If you have the case of a family business, and someone is working within the company, it is just as easy to give them stock options that bypass this anyways. Good business and succession planning can bypass the estate tax and easily pass on a larger family business to ones children. That in and of itself nullifies the "family business" argument.