The West should never have permitted any Mohammedan immigration. The lessons should have been learned long before the Siege of Vienna. Ending immigration now is totally insufficient. Expulsion is very much necessary if the West is to survive into a future that is not mostly semi arid sheep grazing lands.
Islam is destined to remain unchanged in the future, as it has been until now, the only possible outcome is a difficult coexistence with those who do not belong to the Muslim community: in an Islamic country, in fact, the non-Muslim must submit to the Islamic system, if he does not wish to live in a situation of substantial intolerance.
Likewise, on account of this all-embracing conception of religion and political authority, the Muslim will have great difficulty in adapting to the civil laws in non-Islamic countries, seeing them as something foreign to his upbringing and to the dictates of his religion. Perhaps one should ask oneself if the well-attested difficulties persons coming from the Islamic world have with integrating into the social and cultural life of the West are not explained in part by this problematic situation.
We must also recognize the natural right of every society to defend its own cultural, religious, and political identity. It seems to me that this is precisely what Pius V did.