I haven't read Steyn's book yet, but the author of this article doesn't factor in the growing Muslim population in our own country, as well as in Mexico and Central and South America.
You should ignore all that. Your fears are overblown, racist, and bigoted. And insensitive. I'm offended. I demand an apology. And I want your apology plastered all over the mediot airwaves for at least two weeks. Then I might be satisfied, if you give me two million dollars in damages.
As Steyn persuasively argues, demography has already doomed Europe, unless they unexpectedly find enough cultural energy to deal with the problem. But it's probably already too late. Demography is not predictive but actual, since the number of new Europeans reaching adulthood now and over the next twenty years was already determined twenty years ago and cannot be changed.
America is also vulnerable, but is not yet in that dangerous a position because of the relative demographics. We are still reproducing, and most of our immigrants are Latinos. Muslims are still limited in number, though I would agree too many for comfort.
I hear this claim bandied about by the "build the fence and expel em all" cult, but there is no evidence to support the idea that Islam is a growing threat to us in Latin America. Even the "Mohammed Triangle" area of Paraguay, Uruguay and Argentina/Brazil (which bears watching) is all made up of immigrants, not converts. Intelligence and military units of these countries have begun tracking these people, tightening immigration requirements, and restricting visas to Arabs/Muslims.
This could change, of course, and we could see a huge influx of Latinos into Islam. However, the truth of the matter is that evangelical/pentecostal Christianity is the true surge in cultural change in Latin America. Over 70% of the population of El Salvador is now protestant, and 60% of Guatemala.
I fear the "students" on expired visas here far more than the paranoid wet dreams of those who want to check under the sombrero of every border hopper to see if he has an Al-Quaeda membership card tucked up there.