A Wall Street Journal editorial today (subscription required) again suggests that tax cuts increase revenue:

Our primary concern with the Katrina spend-fest is that it puts the economy at risk by putting pro-growth tax cuts in harm’s way. If the 2003 capital gains, dividend and income tax rate cuts are cancelled, as virtually the entirety of the Democratic Party is clamoring for, we get the most destructive of all fiscal storms: a continued federal spending buildup — expenditures are already up 34% under President Bush in five years — slower economic growth, and a smaller future tax base to finance federal spending promises.

This is nonsense on two levels. We know that deficits drive up interest rates and at least partly counteract the effects of tax cuts. In addition, having a larger “future tax base” isn’t particularly helpful for financing “federal spending promises” because keeping the Bush tax cuts in place will (a) increase the debt burden on future generations and (b) reduce the amount of revenue that could be generated from the future tax base without a tax increase.

The trick here is to obscure the underlying supply side fallacies by using more indirect language. But the point is the same, so let me put it more clearly. Almost every serious economist (including former Bush CEA chair Greg Mankiw) agrees that tax cuts don’t increase growth enough to pay for themselves. This means that tax cuts reduce revenue both now and in the future relative to what would have happened if they had not been enacted. And that means that the federal government has less ability to fulfill its spending promises both now and in the future.

(See my previous posts on the Journal for more.)