We are saddened and appalled by the carnage–including of children–at the stadium in Manchester.

Any comments I might make would ring hollow in the light of the magnitude of the suffering inflicted last night on innocent concert goers.

 But I will comment on one very disturbing phrase found time and again in the reporting on atrocities such as this one. This is from CBS:

CBS News confirmed Tuesday that the man who blew himself up the previous night at an Ariana Grande concert in Manchester, England, was 23-year-old Salman Abedi, who was known to British authorities prior to the attack.

So many of these killers were known to the authorities prior to their attacks. The FBI interviewed Tamerlane Tsarnaev two years before the Boston Marathon bombing that left so many dead and maimed.

FBI officials "admitted" that the agency had "missed opportunities" to prevent the bombing. In 2014, some deficiencies were noted

. . .  when an officer from the FBI-led Boston Joint Terrorism Task Force (JTTF) questioned Tamerlan and his parents, the JTTF never asked about Tamerlan’s travel plans. Nor did the JTTF officer question Tamlerlan Tsarnaev’s wife or his ex-girlfriend, who had filed an assault charge against him in 2009. Though the report says that it is “impossible to know what the former girlfriend and wife would have told the FBI in 2011,” the authors also point out that after the bombing, both Tamerlan’s ex-girlfriend and his wife told law enforcement about his growing radicalism prior to 2011.

Now they tell us.

Salman Abedi's rampage also had a lead-up:

[Neighbor] Lina Ahmed, 21, told MailOnline: 'They are a Libyan family and they have been acting strangely. A couple of months ago he [Salman] was chanting the first kalma [Islamic prayer] really loudly in the street. He was chanting in Arabic. 

'He was saying 'There is only one God and the prophet Mohammed is his messenger'.'

Abedi's former school friend Leon Hall told MailOnline he saw the killer last year and said he had grown a beard.

Now, let's be clear. We in Western nations enjoy civil rights, and I doubt that any of us believe somebody should be arrested for growing a beard or for chanting the Koran loudly in Arabic (unless he is disturbing the peace, which sounds like a possibility here).

We don't want to change our values or lessen the guarantees of civil liberties for all on our soil, but what we can do is make sure that political correctness doesn't make the authorities afraid to ask the right questions.

We can also face that there are people who want to come to Europe or the U.S. but don't very much like us very much and indeed in some cases intend harm. 

We, like the U.K., are a welcoming society. But we have every right to insist the immigration be legal and that we can expect reasonable assimilation from those on whom this nation bestows the honor of citizenship. 

Admittedly Salman Abedi is a second-generation U.K. resident, but he lived in an enclave of non-assimilation and most likely hostility to Western values.