An infestation.

All quite voluntary and completely unnecessary:

The most important single bit of information in "Fitna" was not any of the passages from the Qur'an. It was a bit of demographic information: that in 1960 there were about 1,500 Muslims in the Netherlands, and forty-four years later there were close to a million.

Demography is destiny. Look closely at the picture above of the maddened Muslim protesters in Indonesia, threatening death to a Dutch member of Parliament who dared to quote the Qur'an -- entirely accurately -- in a fifteen-minute film. There are already such scenes, intermittently, on the streets of London and Paris. Would you like those countries of Western Europe to routinely have such scenes, and become, as Indonesia did over centuries, or as Kafiristan and Waziristan did over little more than the last 100 years, or as Malaysia has been doing during the last few decades, steadily islamizing, steadily raising the percentage of the population that willingly submits to the Total Belief-System of Islam, with all that that would mean for art, science, human freedom?

"Indonesia, Islamized." By Hugh Fitzgerald, New English Review, 4/9/08 (emphasis added).