from John Cochrane in his excellent blog, The Grumpy Economist, Why Not Taxes?

America in fact already has a more progressive tax system than pretty much any other country. Making it more progressive would increase economic distortions dramatically.

A key principle here is that the overall marginal tax rate matters.  There is a tendency, especially on the left, to quote only the top Federal marginal rate of about 40%, and to say therefore that high income Americans pays less taxes than most of Europe. But that argument forgets we also pay state and sometimes local taxes.

The top federal rate is about 40%. In California, we add 13% state income tax, and with no deductibility we’re up to 53% right there. But what matters is every wedge between what you produce for your employer and the value of what you get to consume. So we have to add the 7.5% sales tax, so we’re up to 60.5% already.

But we’re not done.  The Federal corporate tax is now 21%, and California adds 8.84%, so roughly 29% combined. Someone is paying that. If, like sales tax it comes out of higher prices, then add it to the sales tax. Those on the left say no, corporate taxes are all paid by rich people, which is why they were against lowering them. OK, then they contribute fully to the high-income marginal rate.

What about property tax? The main thing people do with a raise in California is to buy a bigger house. Then they pay 1% property tax. As a rough idea, suppose you pay 30% of your income on housing and the price is 20 times the annual cost (typical price/rent ratio). Then you are paying 6% of your income in property taxes. Add 6 percentage points.

I’m not done. All distortions matter. In much of  Europe they charge taxes and then provide people health insurance. We have a cross subsidy scheme, in which you overpay to subsidize others. It’s the same as a tax, except much less efficient.  In terms of economic damage, and the overall marginal rate, it should be included. If you live in a condo, whose developer was forced to provide “affordable housing” units, you overpaid just like a tax and a transfer. And so on. I won’t try to add these in, but all distortions count.

In sum, we’re at a pretty high marginal tax rate already. The notion that we can just blithely raise another 10% of GDP from “the rich” alone without large economic damage does not work.  This isn’t a new observation. Just about every study of how to pay for entitlements comes to the same conclusion.

Again, my argument is not about sympathy for the rich. It is a simple cause and effect argument. Marginal tax rates a lot above 70% are going to really damage the economy and not bring in the huge revenue we need.