Jason Richwine, a senior policy analyst at the conservative Heritage Foundation who argued in a graduate school dissertation that Hispanic immigrants were less intelligent than white Americans, resigned from his post with the foundation on Friday.
"Jason Richwine let us know he's decided to resign from his position," the Heritage Foundation said in a terse email statement. "He's no longer employed by Heritage."
The foundation declined to comment further, saying, "It is our long-standing policy not to discuss internal personnel matters."
Richwine was also the co-author of a Heritage Foundation study that criticized legislation in the Senate to overhaul the nation's immigration laws, citing high economic costs. The analysis found that the legislation would cost taxpayers roughly $6.3 trillion over the next 50 years.
But reports this week about the content of Richwine's 2009 doctorate dissertation, in which he said the lower I.Q.'s of immigrants should be considered when crafting public policy, set off a furor, with some immigration advocates decrying his writing as racist.
The Heritage Foundation had already come under criticism from both Democrats and Republicans for the study on the costs of the immigration proposal, and news of Richwine's outside writings further undercut the organization's attempt to help shape the immigration debate from the outside.
Supporters of the immigration bill welcomed Richwine's resignation.
"Racism and xenophobia have no place in the debate on immigration reform, period," said Jose Antonio Vargas, the founder of Define American, a pro-immigration group. "I hope this is a lesson for all sides that what the public is looking for is a fair and honest debate on immigration reform, not long discredited racial theories designed divide us rather than unite us."