A co-author of the already controversial new Heritage Foundation study — the one that claims to show immigration reform will cost the U.S. $6.3 trillion dollars — wrote in 2009 that the government should grant immigrants visas based on IQ, and that "No one knows whether Hispanics will ever reach IQ parity with whites, but the prediction that new Hispanic immigrants will have low-IQ children and grandchildren is difficult to argue against." The co-author, Jason Richwine, wrote that for his public policy doctoral thesis, The Washington Post's Dylan Matthews reports. Richwine wrote that the U.S. should use the term "skill-based" instead of IQ-based to "blunt the negative reaction." Thus Richwine is able to provide the missing link between the oafish Donald Trump, who said at CPAC, "Why aren't we letting people in from Europe?" and more mainstream explanations of the controversy among conservatives over immigration. "It's going to be a much easier lift to solve the problem of high-skilled workers," Alabama Rep. Spencer Bachus said in February.

The most obvious problem with Heritage's study is its economic analysis, not social analysis. When CNBC's Larry Kudlow asked Robert Rector, the lead author of the Heritage study, whether it takes into account economic growth from immigration, Rector said, "No." Rector he did hint that he agreed with his co-author's ideas about what kind of immigrants we should let in, saying high-skilled immigrants with higher education levels would bring in more tax revenue and take fewer government benefits. Richwine (pictured above) fretted in his Harvard thesis that these immigrants would never fit in because of their tiny brains:

The average IQ of immigrants in the United States is substantially lower than that of the white native population, and the difference is likely to persist over several generations. The consequences are a lack of socioeconomic assimilation among low-IQ immigrant groups, more underclass behavior, less social trust, and an increase in the proportion of unskilled workers in the American labor market.

The idea that Latinos won't assimilate because they're doomed to low IQs for generations is offensive. But so what? More important, it's wrong. At least half of the variation in IQ is inherited, The Wall Street Journal explained in January, but scientists haven't figured out which genes affect IQ. And even more important for today's political debate, Latinos are assimilating. The New York Times's David Leonhardt explained in April that Latinos are assimilating at about the same rate as earlier immigrant groups — they're "the New Italians," he said. As with Italians, a huge wave of Latinos immigrated here poor, poorly educated, and culturally different. But they become richer and better educated with each generation. RAND Corporation economist James P. Smith found that the average Latino immigrant has a junior high education, but the average Latino immigrant's kid goes to college for almost a year, and the average Latino immigrant's grandkid stays in college longer.

At Reuters, Reihan Salam points out that many people do not call themselves Hispanic, despite their parent or grandparent having been born in a Spanish-speaking country. The vast majority of Mexican-, Cuban-, Dominican-, Chinese-, and Filipino-Americans and Puerto Ricans have two grandparents or less who were born in those countries. The high rate of intermarriage, The American Prospect's Jamelle Bouie writes, could mean that as with Italians before them, it's likely Latinos' old national distinctions will disappear until they're just called "white." By then, there will probably be some other group whose collective IQ the Heritage Foundation is worried about.

Update: The Heritage Foundation emails this statement from vice president of communications Mike Gonzalez: "This is not a work product of The Heritage Foundation. Its findings in no way reflect the positions of The Heritage Foundation. Nor do the findings affect the conclusions of our study on the cost of amnesty to the U.S. taxpayer."