Speaking at a "Stop Amnesty" rally in Richmond the other day, Iowa Rep. Steve King explained why Americans should be banned from Canada.

"If you bring people from a violent civilization into a less-violent civilization," he said, "you're going to have more violence, right? It's like pouring hot water into cold water. Does it raise the temperature or not?" Since Canada's violent crime rate is less than half that of the United States, the next step should be obvious: Secure the border – the northern one – to make sure Canada is not overrun by violent Americans.

Obviously, King was trying to make a different point: He was trying to explain why America should seal its southern border to keep out immigrants from Latin America. But his argument works just as well the other way around. For that matter, it works just as well as a rationale for banning immigration from South Carolina to Maine.

That's not the only reason King is – with apologies to Australian lawmaker Tony Abbott – the "suppository of all wisdom" about immigration. To make matters worse, his argument is empirically wrong on two counts.

First, he says crime in the Americas increases the farther south you go. That would be news to nations such as Argentina and Chile, whose crime rates are lower than ours. Second, he is wrong to suggest adding more immigrants would raise the U.S. crime rate. In fact, the opposite would happen.

That is not new information. Five years ago the Public Policy Institute of California noted that U.S.-born adult men are more than three times as likely to be in prison than foreign-born men, and that "noncitizen men from Mexico ages 18-40 – a group disproportionately likely to have entered the United States illegally – are more than eight times less likely than U.S.-born men in the same age group to be in a correctional setting."

Similar findings have been reported again and again. As many observers have noted, U.S. crime rates fell rapidly from 1990 to 2010. During that same period, the number of illegal immigrants in the U.S. tripled, and foreign-born residents of all kinds grew from 7.9 percent of the population to 12.9 percent. Immigrants from Latin American countries have lower incarceration rates than native-born Americans and, according to the Immigration Policy Institute, "this holds true especially for the Mexicans, Salvadorans and Guatemalans who make up the bulk of the undocumented population."

To be fair, the crime picture is not uniformly sunny. For example: The U.S.-born children and grandchildren of Latino immigrants tend to start committing crimes at higher rates than their parents and grandparents. Perhaps it's the bad environment, eh? To borrow King's analogy, maybe America's boiling cauldron of violence tends to heat up the cool waters of immigration that get poured into it.

King's remarks raise another issue. Ostensibly, he was speaking about illegal immigration. But his comments apply just as well to immigration of the legal kind. This might be awkward for immigration hawks, many of whom insist they don't mind if foreigners come to the U.S. legally. Then again, maybe not: King's visit was arranged by the hard-line group NumbersUSA.

NumbersUSA does not simply want to reduce illegal immigration. It wants to reduce all immigration. In fact, it wants to limit every form of population growth.

"The 1990s saw the biggest population boom in U.S. history," the group says on its website. "This is truly astounding news coming three decades after widespread agreement among Americans that the country was mature and probably already overpopulated. No wonder Americans became increasingly alarmed at their deteriorating quality of life due to sprawl, congestion, overcrowded schools, lost open spaces and increasing restrictions on their individual liberty caused by the new population explosion!"

Population control? To the Tea Party Patriots and other conservatives who helped organized the Richmond event, that should sound more like a UN-driven, big-government conspiracy than sound, small-government philosophy. If so, then they might want to read a recent piece about NumbersUSA in The Atlantic.

"The Little Group Behind the Big Fight to Stop Immigration Reform" explains that while opposition to amnesty "is generally considered a right-wing view . . . NumbersUSA's roots are more unorthodox than that – in the population-control movement that has counted environmentalists and abortion-rights activists among its allies. When [Executive Director Roy] Beck started the group in 1996, he was working for John Tanton, a reclusive 79-year-old ophthalmologist who lives in rural Michigan and once founded local chapters of the Sierra Club and Planned Parenthood."

Granted, politics makes for strange bedfellows. But some Tea Partiers who wake up to their newfound partners' full agenda might want to chew their own arms off. In fact, they might want to rethink the entire conservative platform on immigration. Nothing says "big government" like controlling the free movement of individuals through massive federal programs, electrified fences, biometric ID cards, and mandating government permission slips before businesses can hire willing workers.

To borrow from King one last time: If you have a free society and you pour all those elements into it, you're going to have less freedom, right?

This article originally appeared in the Richmond Times-Dispatch.