As some one who is strongly for estate taxes, I propose we call them "aristocracy-prevention taxes." Accumulation of wealth solely based on inheritance is a shitty way to run a society.
I'm totally fine with it being much, much lower than the assets I'll have when I die. I plan to leave the vast majority of my assets to charity, and even if I didn't, I wouldn't WANT to leave a lot of money to my children. I've met a number of people who grew up with large trust funds, and in every case I think the kids were worse off for it.
