"You don’t tax the rich because you need their money in order to feed a hungry kid or fix a crumbling bridge. You tax the rich because they are too damn rich and extreme concentrations of wealth especially, but also income, are bad for the functioning of the economy, are bad for democracy. That’s the rationale for taxing the rich. Not because we can’t do other things unless we get money from them to pay for it." - Professor Stephanie Kelton.
http://www.taxresearch.org.uk/Blog/2018/07/29/why-we-need-a-wealth-tax/