The Laffer Curve is the simple notion that higher tax rates don’t necessarily generate as much loot as politicians expect because taxpayers have less incentive to earn and/or report income.

And it works in both directions. Lower tax rates don’t lose as much revenue as politicians fear because better tax policy leads to more taxable income.

In a few cases, higher tax rates may even lose revenue and lower tax rates may generate additional receipts. The IRS collected a lot more tax from upper-income taxpayers, for instance, after Reagan slashed the top tax rate from 70 percent to 28 percent.

Over the past few years, I’ve shown lots of evidence from around the world (England, Spain, and France) and in various states (Illinois, Oregon, Florida, Maryland, and New York) to make the case that it is foolish to ignore…