A high marginal tax rate "doesn't seem to hurt economic growth and maybe even spurs it" by putting more money in consumers' pockets, according to Matthew Dimick, a professor at the University at Buffalo School of Law who studies the relationship between law and inequality.
Proponents of lower taxes, though, point to America's massive, innovative corporations as a success story. In a post on Jan. 25, the American Enterprise Institute's Jim Pethokoukis, a CNBC contributor, also questioned how a higher tax burden on the rich would affect business formation and risk taking.
"America must be doing something right since it has Apple, Google, and Amazon, and Europe doesn't," he wrote.
Yet, high marginal tax rates in the 1960s didn't inhibit development of such watershed technologies as the microchip or satellite communications.
Western Europe, which broadly has higher income tax rates than the U.S., has seen income inequality grow much more slowly than the U.S. The share of national income received by the top 1 percent in the region grew only to 12 percent in 2016, versus 10 percent in 1980.
France, Germany and the United Kingdom all had top individual income tax rates of at least 45 percent in 2017, compared with under 40 percent in the U.S., according to the OECD. Austria, Belgium and Israel all topped 50 percent. Those rates do not include all taxes separate from those on income, which are generally higher in Europe, where governments broadly cover more social services.
Of course, detractors of raising taxes on the wealthy would also point to the fact that those countries' economies are largely growing at slower rates than the United States. And, even outside the U.S., governments have not had an easy path when attempting major tax hikes. France faced resistance when former President Francois Hollande tried to raise the tax rate on millionaires to 75 percent. The country abandoned the idea in 2014.