Iowa Rep. Steve King brought the issue of assimilation to national attention once again on Monday when he claimed that he wasn’t making a statement about race but rather about immigration and culture when he posted a controversial tweet saying the U.S. “can’t restore our civilization with somebody else’s babies.”

In his original tweet Mr. King said: “We can’t restore our civilization with somebody else’s babies.” He praised anti-Islam Dutch politician Geert Wilders in the tweet, saying: “Wilders understands that culture and demographics are our destiny.”

The original Twitter post spawned accusations of racism from Democrats and denunciations by some Republicans, but Mr. King told The Washington Times his point was that the U.S. needs to focus on assimilating those it brings to the country, not on excluding everyone else.

Mr. King, who has an extensive history of making highly inflammatory xenophobic comments, appears to be seeking cover for his remarks behind a misguided concern over slower assimilation rates. To the surprise of Mr. King and his supporters, the newest generations of immigrants are assimilating into American society as fast and broadly as the previous ones, with their integration increasing over time “across all measurable outcomes,” according to a report published by the National Academies of Sciences, Engineering and Medicine.

Immigrants’ education levels, the diversity of their jobs, their wages and their English-language fluency improved as they lived for more time in the United States. The gains for their American-born children, the study concluded, were even greater.

“The force of integration is strong,” said Mary C. Waters, a sociologist at Harvard who led the panel of 18 immigration scholars who wrote the more than 400-page report. “However we do it, we are good at it,” she said.

Professor Waters said the report should allay fears that recent immigrants committed crimes more frequently than Americans, that they were generally in poor health and burden public health care systems, or that they were failing to learn English.

The report looked at 41 million foreign-born people — including about 11.3 million immigrants here illegally — and their children born in the United States, about 37 million Americans. Taken together, the two generations include one in four people in this country. English language learning “is happening as rapidly or faster now than it did for earlier waves of mainly European immigrants in the 20th century,” the report found.

“The desire on the part of immigrants to learn English is very high,” Professor Waters said the researchers found. Concerns that the latest generation of immigrants is seeking to impose its languages on American society “is not something people should be worried about,” she said.

If Congressman King is truly worried about the rate of assimilation in America, this extensive study should ease his concern. Given his penchant for racist rhetoric however, I believe what truly ails the Iowa Congressman isn’t the pace of assimilation but rather the browning of America.

What he fails to see however, is that this beautiful, multicolored mosaic, which he finds so reprehensible, is precisely what sets us apart from the rest of the world, and gives us our competitive edge. Our multiculturalism has been a work in progress since the day our Republic was established, and it is every bit as American as the glorious corn fields that decorate the Congressman’s home state.