Jason Richwine, the co-author of a study by the Heritage Foundation claiming immigration reform would add $6.3 trillion to the deficit, has resigned from his position at the conservative think tank.

Heritage had already sought to distance itself from Richwine amid reports that he suggested in a Harvard thesis and a panel at the American Enterprise Institute that the United States discourage various non-white groups from immigrating because they have lower IQs. He also wrote articles on Hispanic incarceration rates for a white nationalist website.