“The reason that unemployment is high clearly has nothing to do with taxes. Consequently, there is no reason to think that reducing taxes further will do anything to raise employment by reducing the tax wedge.
Additional evidence on this point comes from a new study by the Organization for Economic Cooperation and Development on taxes paid by average workers in its 34 member countries. The data [above] are for a single worker without children.
As one can see, the United States is a low-tax country with a total tax wedge of 29.5 percent. Three-fourths of O.E.C.D. countries have a larger tax wedge on average workers.
I have also included the latest data on the percentage of workers employed as a share of the working-age population. I think this is a better measure of the health of the labor market than the unemployment rate, which goes up and down for a variety of reasons unconnected to taxes.
Here, too, there is little evidence that taxes affect employment one way or another. Almost half of the countries with a bigger tax wedge employ a larger percentage of their working-age populations than the United States does, and more than half of those with a smaller tax wedge have lower employment ratios. […]
There is simply no evidence that cutting taxes at the present time will do anything to raise employment.” - Bruce Bartlett: Taxes and Employment