Nugatory, Really? Really?

Martin Wolf of the Financial Times has occasionally written some compelling economic critiques. I think I first read something scathing by him courtesy of a Krugman link.
So anyway, he's reporting that two Very Important Economists — VIEs — say higher tax rates for the rich must include increases in capital gains taxes, although he strangely declines to use that term. (Maybe there are other kinds of income from capital, I wouldn't know.)
Anyhoo, thanks for the Word O' Teh Day, Martin.
Nugatory: without power.

At present, the far lower taxation of income from capital than from work makes the taxation of ultra-high incomes nugatory.

Oh, yeah. The bottom line:

Historically, the emergence of huge inequalities in wealth and political power has destroyed democratic republics, turning them into entrenched oligarchies, instead. This is bad politically. It is almost certain to be bad economically, too, as the oligarchy uses its power to reduce economic competition...The case for reform has become overwhelming. 

The Financial Times. The Financial Times.