Ezra Klein the other day posted an analysis of state taxation that deserves more attention than the issue gets. Although he didn't quite put it this way, what he showed -- based on Katherine Newman's book, "Taxing the Poor" --  is that Republican states tend to raise a far higher share of their taxes from the poor, and less from the rich, than Democratic states. Here's the graph:

The South is the most reliant upon regressive sales taxes, followed by the West, followed by the Midwest, followed by the Northeast. The reverse is true of the property tax, which is progressive.

The basic picture here is that, at every level of government, the conservative movement fights for the most regressive possible distribution of the tax burden. In 2003, the Republican governor of Alabama Bob Riley had an epiphany of sorts that the state's viciously regressive tax code, which taxed the poor at several times the rate of the rich, was a moral affront, and he set about to reform it. Conservatives were aghast. Grover Norquist helped pump huge sums into the state to fight Riley's reform, funneling the money through the Christian Coalition, which was obviously acting on the Bible's injunctions against coddling the poor with low or even equal tax rates. (I described the episode in my book.) They succeeded, and Norquist gloated, "Every Republican governor who thinks of raising taxes next year will walk past Traitor's Gate and see Bob Riley's head on a pike.

When conservatives discuss the distribution of the tax burden, they tend to focus on the federal level (and even then they usually ignore the more regressive federal taxes.) But, of course, in our federal system, we divide the functions of government between the national, state, and local levels. Given that the latter two tend to charge higher rates to the poor -- especially in conservative states -- some level of progressivity at the national level is needed merely to keep the overall tax level flat.

The regressivity of state taxation is not unrelated to the need for progressive taxation at the national level. And it's not something that just happens, either. It's a vital element of conservative policy, one which conservatives will go to great lengths to defend in the arre instances when it's challenged.