If the economic crisis necessitates a second stimulus—and it probably will—then a payroll-tax holiday deserves a look. But it’s only half a good idea. A whole good idea would be to make a payroll-tax holiday the first step in an orderly transition to scrapping the payroll tax altogether and replacing the lost revenue with a package of levies on things that, unlike jobs, we want less rather than more of—things like pollution, carbon emissions, oil imports, inefficient use of energy and natural resources, and excessive consumption. The net tax burden on the economy would be unchanged, but the shift in relative price signals would nudge investment from resource-intensive enterprises toward labor-intensive ones. This wouldn’t be just a tax adjustment. It would be an environmental program, an anti-global-warming program, a youth-employment (and anti-crime) program, and an energy program.