But, in truth, nobody really should run for office on the supply-side revenue effects of tax cuts, either. As it turns out, they present a dry and technical question of limited interest to the general electorate. It is true that tax cuts can promote growth, and that the growth they promote can help generate tax revenue that offsets some of the losses from the cuts. When the Reagan tax cuts were being designed, the original supply-side crew thought that subsequent growth might offset 30 percent of the revenue losses. That’s on the high side of the current consensus, but it’s not preposterous. There is, however, a world of difference between tax cuts that only lose only 70 cents on the dollar and tax cuts that pay back 100 cents on the dollar and then some.
There is considerable debate among economists and federal legume-quantifiers about how large supply-side revenue effects are. The Congressional Budget Office did a study in 2005 of the effects of a theoretical 10 percent cut in income-tax rates. It ran a couple of different versions of the study, under different sets of economic assumptions. The conclusion the CBO came to was that the growth effects of such a tax cut could be expected to offset between 1 percent and 22 percent of the revenue loss in the first five years. In the second five years, the CBO calculated, feedback effects of tax-rate reductions might actually add 5 percent to the revenue loss — or offset as much as 32 percent of it. That’s a big deal, and something that conservative budget engineers should keep in mind. But the question of whether the CBO accounts for tax cuts at 100 cents on the dollar, 99 cents on the dollar, or 68 cents on the dollar is hardly the stuff that a broad-based political movement is going to put at the center of its campaigns. Federal spending, on the other hand, is a national crisis.
And that’s one thing the gentleman from Clayton has right: Tax cuts aren’t really the problem. The hot action is on the spending side of the ledger, and nobody wants to touch it. The problem with magical supply-siderism is that it gives Republicans a rhetorical and intellectual framework in which to ignore spending — just keep cutting taxes, the argument goes, and somebody else will eventually have to cut spending. The results speak for themselves: Tom DeLay and Dennis Hastert and Trent Lott and Bill Frist all know how to count, but, under their leadership, Republicans spent all the money the country had and then some. Deficits boomed, and Republicans’ claim to being the responsible britches-wearing adults when it comes to spending got unpantsed. Cutting taxes is easy. Cutting spending is hard.
Professor Laffer appreciates this. “It’s hard to win on spending. If it’s a Louisiana Purchase or the Cornhusker Kickback or earmarks, you can win on some of those, but it’s real hard. If you’re on a college campus, you can whip the kids into a wild rage on defense spending, on Iraq and Afghanistan. People love getting government benefits and they hate paying for them.” Supply-side icon Jude Wanniski understood the politics of spending cuts and described his own approach as the “Two Santa Claus Theory.” Short version: Nobody votes for Scrooge. Tax cuts give Republicans an opportunity to distribute economic benefits through the tax code the way Democrats distribute them through appropriations, and the exaggeration of the supply-side effect gives them an opportunity to pretend like those benefits are cost-free.