The “Unite the Right” rally in Charlottesville, Va., shocked many Americans with its unashamed and open embrace of white supremacist and Nazi ideology. It set off a passionate national discussion on how to best deal with racism and racist groups. There is an unconventional starting point: revoking the tax exemption of white supremacist groups.

We suspect that many Americans would also be shocked to learn that a number of white supremacist groups — including the New Century Foundation, which hosts an annual conference that has included neo-Nazis, white supremacists, Ku Klux Klan members, Holocaust deniers and eugenicists — are exempt from taxation. (The National Policy Institute, directed by Richard Spencer, was another, until it lost its tax-exempt status this year after failing to file federal tax returns.) A recent Associated Press report said that over the past decade, four prominent white nationalist groups alone received over $7.8 million in donations.

Like museums, churches and schools, these groups do not have to pay taxes on a majority of their revenue. Donors to these groups can deduct their gifts, and real estate that the groups own is generally exempt from property taxes. In addition, in the eyes of the organization and the public, being tax-exempt confers a certain legitimacy.

The I.R.S., the agency in charge of enforcing these rules, must decide whether groups qualify for tax exemptions. It makes that decision impartially, meaning that organizations that, say, promote racist ideology are generally eligible for nonprofit status as long as they are organized for a qualifying purpose and otherwise meet the criteria for exemption. For many white supremacist groups, that claim is on educational grounds (established by I.R.S. criteria). After all, many on the far right, like Mr. Spencer and the operators of organizations like VDare, declare that they do not hate others but rather promote whiteness.