If today’s immigrant wave were likely to vote Republican, all right-thinking people would be demanding deportations and a mile-wide belt of barbed wire and minefields along the border.

That quote from Glenn Reynolds and this one from (immigrant) Eugene Volokh: are particularly apt in today's environment.

I think, though, that the “Pilgrims = Illegal Aliens” equation illustrates the exact opposite. The whites immigrated to America — and took over the place. (I’m glad they did, but I can surely understand why the Indians might have disagreed.) Likewise, Jews immigrated to Palestine (adding vastly to the numbers already present), sometimes illegally — and eventually there were more Jews in some parts than Arabs, so Jews started running the place. Now Israelis are sensibly objecting to Palestinians’ asserted “right of return” to their and their parents’ homes, because if enough Palestinians are allowed to immigrate into Israel, they’ll start running the place.

The bottom line is that for all the good that immigration can do (and I’m an immigrant to the U.S., who is very glad that America let me in, and who generally supports immigration), unregulated immigration can dramatically change the nature of the target society. It makes a lot of sense for those who live there to think hard about how those changes can be managed, and in some situations to restrict the flow of immigrants — who, after all, will soon be entitled to affect their new countrymen’s rights and lives, through the vote if not through force.

I sometimes pose for my liberal friends a stylized thought experiment. Say that they live in a country of 3 million people (the size of New Zealand) where 55% of the citizens are pro-choice and 45% are pro-life (1.65 million vs. 1.35 million). Now the country is facing an influx of 1 million devoutly Catholic immigrants, who are 90% pro-life. If these immigrants are let in and become citizens, the balance will flip to 2.25 million pro-life to 1.75 million pro-choice (56% to 44% pro-choice); and what my friends might see as their fundamental human right to abortion may well vanish, perfectly peacefully and democratically.

It’s unlikely that any constitutional protection will stand in the way: Even constitutions can be amended, and new judges can be appointed. Nor can one rely on “education” or “assimilation” — what if the immigrants simply conclude that their views on abortion are just better than the domestic majority’s? I think many of the current residents may rightly say “We have nothing against Catholics; but we don’t want our rights changed by the arrival of people who have a different perspective on the world than we do.”

Letting in immigrants means letting in your future rulers.

I also find it interesting that a political persuasion that believes that the state should manage and regulate (and this is just a few minutes of the As) Automobile safety, automobile emissions, airplane design, AM radio, ambulatory care centers, automobile fuel efficiency, adolescent esteem, advertising content, automobile propulsion technology, airplane safety, ambergris distribution, airline operation, airport access, airport fees, adenoid removal reimbursement, American flag usage, anti-coagulants, anti-histamines, armor piercing bullets, air conditioner coolant, air conditioner efficiency and air quality (both indoor and outdoor) with a brutality in terms of prosecutorial resources, swingeing fines and disproportionate prison sentences that would astound our founders literally throws it's hands up at the border saying "weuns cain't do nothin' 'bout thiiyas, its justa happenin' y'know?".