I've always wondered why how Republicans are able to get their political coalition to support an economic policy consisting almost entirely of deficit-financed regressive tax cuts. The policy has a terrible track record of promoting growth, and it even has a terrible track record of shrinking the size of government. So why are Republicans so devoted to it?

My theory, which I explain at more length in my book, is that you have a tiny group of supply-side true believers. Then you have a larger group of rich people who benefit from regressive tax cuts. This coterie has managed to grab the reins of the right-wing policy apparatus and spew an endless stream of propaganda supporting those policies. Meanwhile, most people have very little understanding of economic and fiscal policy, so it's easy to convince anybody with a general predilection for small government that regressive, debt-financed tax cuts are advancing the small government cause.

A perfect example is this column by Nick Gillespie, editor of the libertarian magazine Reason. Gillespie is not a policy wonk, nor is he a reflexive GOP partisan. So it is instructive to watch him work toward the position that the Bush tax cuts must be made permanent. Gillespie begins by showing a chart of the nominal revenue and spending totals since 2002. He concludes:

Here's the actual federal revenues gathered under Bush (whose budgets cover fiscal years 2002 through 2009, which actually includes some spending signed by Obama due to the inability of the government to hit its own budget deadlines). Prior to 2008, when the current recession had gone big, you'll notice exactly one year-over-year decline in revenue. ...

So if the feds were generally pulling in more bucks each year - even with those tax cuts that so decimated federal revenue - where did the deficits come from?

Oh, that's right: From massively expanded spending that happened both under a lying GOP Congress and a feckless Democratic majority. The story of the Bush years isn't to be found on the revenue side of the ledger, but on the spending side

Granted, I've been an English major all my life and I'm not much for book-larnin' and those fancy words and plus and minus signs, but when I look upon these two charts, something hits me in the mush with all the force of a friendly Dick Cheney shotgun blast: " It's the spending, stupid ."

There are numerous, massive problems with the analytic method on display here. First of all, focus on this assertion: "Prior to 2008, when the current recession had gone big, you'll notice exactly one year-over-year decline in revenue, you'll notice exactly one year-over-year decline in revenue." In fact,the government also experienced year-to-year drops in revenue from 2001 to 2002, reflecting both the shaky economy and the effects of the Bush tax cuts. Gillespie oddly fails to include those years, instead leaning on the strange implication that the Bush tax cuts began in 2002. Moreover, he excludes the drop in nominal revenue in 2008, which he attributes to the recession. Obviously, though, economic conditions work both ways. When the economy is expanding, revenue tends to rise even in the absence of policy change. When the economy is contracting, it tends to drop. Gillespie's approach is to ignore the state of the economy when it creates data that seems to bolster his argument, and to take account of the economy when it creates data that undermines it.

A more accurate way to report Gillespie's statistic would be that nominal federal revenue has fallen in four of the eight years since the Bush tax cuts have taken effect. Yet that statistic, too, is misleading for various reasons, the most important being...