"Catalogue of blunders left Berlin attacker free to kill as Europe-wide manhunt continues in search for Tunisian suspect," proclaims the headline of the London Telegraph.

But is "blunders" really the right word? Isn't it policy or willful blindness that left the Tunisian suspect free to kill?

Andrew McCarthy writes that Islamist enclaves, the creation of Europe's immigration policy, are a bigger problem than infiltration of jihadists from the Middle East. McCarthy writes:

Notwithstanding that they arrested and held the wrong man for several hours, it turns out that German authorities have been well aware that Amri posed a danger. He is yet another of what my friend, the terrorism analyst Patrick Poole, has dubbed “known wolves” — Islamic terrorists who were already spotlighted by counterterrorism investigators as likely to strike.

Amri, who is variously reported to be 23 or 24, arrived in Germany in July 2015 as an asylum-seeker. He was able to remain because of Chancellor Angela Merkel’s suicidal open-door policy for refugees from the Muslim Middle East and North Africa. Prosecutors in Berlin attempted to deport Amri back in June, after learning three months earlier that he was planning “a serious act of violent subversion.” He is reportedly a follower of Abu Walaa, an Iraqi sharia-supremacist firebrand who was recently arrested on suspicion of being a top ISIS leader and recruiter in Germany. His terrorist activities aside, Amri has also been involved in narcotics trafficking, theft, and the torching of a school.

That last felony occurred in Italy, where the “refugee” was sentenced to five years in prison before being welcomed into Deutschland. All that baggage, and still the Germans allowed him to remain. Reportedly, officials felt they could not deport him because he did not have a passport and the Tunisian government would not acknowledge him (despite the fact that the Tunisian government had convicted him in absentia of a violent robbery). That might explain a brief delay in repatriating him; it does not explain a legal system that permits a suspect with a lengthy, violent criminal record to remain at liberty while he is suspected of plotting mass-murder attacks.

Western policy has allowed for the creation of enclaves where "known wolves" can flourish:

The main threat posed by the West’s mass-acceptance of immigrant populations from sharia cultures is not that some percentage of the migrants will be trained terrorists. It is that a much larger percentage of these populations is stubbornly resistant to assimilation. They are thus fortifying sharia enclaves throughout Europe. That is what fuels the jihad. It would be foolish to think it couldn’t happen here, too.

We should not say that the atrocity in Berlin was the product of blunders–that lets German leaders off the hook too easily.

It is admirable that nations want to be generous to outsiders, but this impulse should not be suicidal. Ms. Merkel had more moral obligation to the twelve who were killed and the others who were injured in the Berlin attack than to strangers who are too numerous to be vetted properly.