Its a practical reality. It doesn't necessarily have to be along religious grounds, you can change social acceptance, stereotypes held, public perception, integration (and it can change by itself).

But if you don't deal with the root causes that result in people starting down the path that ends in radicalisation, then you won't stop radicalisation among your own population - and that really is the key here (and across most of Europe) that the terror isn't imported, its been home grown.

And part of understanding what alienates Muslims involves talking to them, particually young muslims.

"One Nation Under God, has turned into One Nation Under the Influence of One Drug"
[Link]

Intelligence is only so much use. And in incidents where 'one person' acts alone, or without a cell and cell structure, its largely meaningless.

In truth, if someone decides to drive a truck for allah through a crowd, there isn't really anything you can do to prevent it. In order to catch terrorists prior to the 'act' you need a conspiracy.

Problem is, terrorist groups, over time, switch more from being organisations into being loosely affiliated, self financed, independent groups associated to an idea. At which point, luck is more a factor in catching them, than intelligence.

Which seems to be more what we've been seeing recently. Not carefully planned IS operations, but what are generally called Lone Wolf terrorism.

Problematic, as it doesn't seem that refugees are particularly deterred by the idea of dying whilst illegally crossing borders. Shutting the 'borders' will just create a refugee crisis in countries of first receipt, who if everyone leaves them 'to it' will just 'encourage' people to cross their borders.

The reality of Europe is that closed borders isn't really viable, especially when you start talking Holland, Belgium, Austria, Italy, France... The practical reality is that these countries have too much in the way of uncontrolled borders, and no real check points, and no means of actually closing down a border without isolating themselves economically.

"One Nation Under God, has turned into One Nation Under the Influence of One Drug"
[Link]

Which is what we should have been doing since the first year of the camps, taking people from the camps, not leaving the problem to escalate for several years and creating very desperate people who would do anything to try to get to a life outside the squalid hole that the camps (and the people who prey on people in the camps) had become.

"One Nation Under God, has turned into One Nation Under the Influence of One Drug"
[Link]

Then that has to change. If it was a traditional war, the borders would be defended real quick.
This is really a question of balance. At what point do other considerations become secondary to the defence of a country>
How many people must die before attitudes change?
Can you put a figure on it? Because in your world of logical pragmatism there must be a practical answer to that question.
And we haven't even moved on to the potentially irreversible damage we are doing to our societies by allowing a backward aggressive religion like Islam into our countries. If there was ever an example of bringing problems on ourselves this is it. Sometimes you have to stop playing the liberal and recognise that not all belief systems are deserving of tolerance because they are themselves intolerant.

I was with you until the last bit. Migration is not the cause of terrorism but those who deal in it are here because of migration. Surely you can't reasonably deny that. Plenty of people were predicting exactly what would happen and now it is happening some people are still rationalising it.

I would ask again. How many people will have to die before they admit that it was an error of judgment.

Its more or less true. Since 9/11, the number of Britons killed by Islamic terrorism, equates roughly to the average number of people killed in Road Traffic incidents in three and a half days (specifically in 2007).

To put WWI in a context, it has nothing on two years of Spanish Influenza, between 1920-22.

An interesting side note, is despite the threat of terrorism, homicide rates in the UK are dropping quite dramatically.

"One Nation Under God, has turned into One Nation Under the Influence of One Drug"
[Link]