Tipping is racist. That’s the argument being forwarded by some liberal activists and politicians as a way of stigmatizing laws that exempt certain professions, mainly restaurant workers, from the federal minimum wage. However, there is little historical evidence for the argument. I don’t think tipping was particularly racial … It was more a matter of customers showing off their wealth, said Gerald Friedman, professor of economics and history at the University of Massachusetts at Amherst and associate editor of the scholarly journal Labor History. Nevertheless, activists pushing for a higher minimum wage have pushed the argument now that their movement has gained ground. Nineteen states are set to phase in higher minimum rates this year, according to the National Conference of State Legislatures. That has brought more attention to the exception for tipped employees in most minimum wage laws. Those employees, mostly in the service industry, can legally be paid less the standard minimum on the grounds that their tips make up for it.