The income effects in an economy always sum to zero.

There are 11 states in the United States that in the last 50 years instituted an income tax. So I looked at each of those 11 states over the last 50 years, and I took their current economic metrics and their metrics for the five years before they put in the progressive income tax... Every single state that introduced a progressive income tax has declined as an overall share of the U.S. economy.

There are several states that move from Karl Marx-like policies to Adam Smith-like policies and back again in a weekend. So for the states with huge volatility in their income tax policies over time, the differences in growth rates in those periods are really amazingly consistent with tax rates really mattering.

There are lots of other things that affect state growth besides state taxes. However, the reason I look at taxes is because these are policy variables that can be changed by state governments in order to get better results than they otherwise had.

I mean, everyone agrees with stress tests for banks. I mean that's clear. But banks should do that on their own. And they should worry about their own capital functioning. That's what they should do. It shouldn't be a government function.

Let's take the nine states that have no income tax and compare them with the nine states with the highest income tax rates in the nation. If you look at the economic metrics over the last decade for both groups, the zero-income-tax-rate states outperform the highest-income-tax-rate states by a fairly sizable amount.

The income effects in an economy always sum to zero.