[pwg]

Yes, but solved only by passing the 16th amendment, which specifically authorized the federal income tax.

The article is, in a round about way, arguing that a wealth tax would need just such a constitutional amendment as well. And in today's political environment it would be much easier to just hike the existing income tax rates than obtain the majorities necessary for passing a constitutional amendment.

[defen]

That won't do much to combat wealth inequality though, because the ultra-wealthy typically do not have high incomes, at least relative to their overall wealth.