By Aaron BlakeMay 10, 2013 at 8:16 p.m. UTCJason Richwine, the co-author of a controversial immigration study released this week by the Heritage Foundation, tells Post Politics that he has resigned his position with the organization."Yes, that's right," Richwine wrote in a brief e-mail. Heritage confirmed that he resigned.Support our journalism. Subscribe today.arrow-right The study written by Richwine and Robert Rector argued that the immigration reform bill would cost $6.3 trillion, but it was widely panned by conservative groups pushing for immigration reform as not accounting for the economic benefits of immigrants. Complicating matters were a series of revelations about Richwine, including that he had written a doctoral thesis at Harvard University arguing that the United States should focus its immigration efforts on those with high IQs and that he had written for a Web site that describes itself as "nationalist." Richwine's departure was first reported by Slate's Dave Weigel.Today's HeadlinesThe most important news stories of the day, curated by Post editors and delivered every morning.