The estate tax has been around on and off for more than 200 years. In the late 18th Century and episodically in the 19th, it was used to pay for wars. It was last repealed in 1902, after the Spanish-American War, was last reinstated in 1916 and has been with us ever since. It certainly hasn't achieved that purpose. It's hard to see where it has had a positive impact on income redistribution at all.
Income equality is greater now than ever.
And that's the big gorilla of a problem facing efforts to do away with it. This tax may not achieve any productive revenue-raising aims, but repealing it is politically difficult because there's no way around the fact that it benefits the rich. Still, it's time to lay it to rest.