In Bloomberg, Megan McArdle recently argued that tax cuts are no longer good politics for Republicans. She asserts that pro-growth politicians have incrementally painted themselves into a corner on this over the last three decades. In order to sell each particular tax cut to the middle class, conservative legislators sweetened each pot by cutting middle-class tax rates more than the tax rates of the rich. Because this has been done for each tax cut iteration, the overall effect has been to make the tax code even more progressive. In the end, the tax cutters had undercut their own message by solving the tax problems of the middle class. As a result, the issue no longer resonates today with them.

To counter McArdle, I suspect pro-growth economists will argue that tax cuts are, nevertheless, still effective at stimulating economic growth, which brings prosperity to all. For this reason, tax cuts are still in the long-term interest of the middle class even if they only directly affect the rich. They can point out that the tax rates of the rich have a much bigger impact on the economy than the tax rates for everybody else. This is because a larger percentage of their income is directed towards productive investment. The more it’s taxed away, the less it’s available for capital investment.