The refined antennae of Western liberals mean that whenever one raises the question of whether there will be any Italians living in the geographical zone marked as Italy a generation or three hence, they cry, "Racism!" To fret about what proportion of the population is "white" is grotesque and inappropriate. But it's not about race, it's about culture. If 100% of your population believes in liberal pluralist democracy, it doesn't matter whether 70% of them are "white" or only 5% are. But if one part of your population believes in liberal pluralist democracy and the other doesn't, then it becomes a matter of great importance whether the part that does is 90% of the population or only 60%, 50%, 45%.
Since the president unveiled the so-called Bush Doctrine--the plan to promote liberty throughout the Arab world--innumerable "progressives" have routinely asserted that there's no evidence Muslims want liberty and, indeed, that Islam is incompatible with democracy. If that's true, it's a problem not for the Middle East today but for Europe the day after tomorrow. According to a poll taken in 2004, over 60% of British Muslims want to live under Shariah--in the United Kingdom. If a population "at odds with the modern world" is the fastest-breeding group on the planet--if there are more Muslim nations, more fundamentalist Muslims within those nations, more and more Muslims within non-Muslim nations, and more and more Muslims represented in more and more transnational institutions--how safe a bet is the survival of the "modern world"?
Read, of course, the whole thing.
A personal note: as one who has chosen a childfree life, I can't help feeling partly responsible for this sort of thing - but, then again, do I want my descendants living in the 9th Century?