[Flamenspiel]

Originally Posted by Itse

I agree. They will also surely do that, as they have done everywhere in Europe. It's just not that easy, as refugees quite commonly don't have much in the way of paperworks, and typically there's no police or government left in the places where they came from who could identify the guys that could be a problem.

Security in an open, democratic society will always be imperfect. It's the price of freedom and the price of giving the refugees a chance.

A quick hypothetical. Let's imagine you're the Supreme Beloved Leader of Canada (but otherwise a rather nice guy).

You are informed that over time 100,000 refugees will come to Canada, and you have to make a choice as to whether to take them in or not.

Your Head of National Security informs you that accepting those refugees will result in about 10 new terrorist attacks in Canada that will kill 10 people on average. They will try to screen them as best they can, but no matter how hard they will try, a total of 10 new terrorists will appear in Canada and 100 Canadians will die in terror attacks on Canadian soil.

On the other hand your Human Rights Counselor informs you that if you don't accept those refugees, about 5% of those people will die somewhere in the Middle-East, and another 1% will join terrorist organizations, most likely ISIS or their affiliates. That's 5000 dead refugees before any new terrorists appear, and 1000 new terrorists that will additionally kill an unknown but probably very large number of people somewhere. Mostly those new terrorists will stay in Syria and Iraq, but obviously there's no way to guarantee that none of those new terrorists will kill Canadians somewhere, like in Paris. Or Toronto.

So, take in refugees or not?

This is a simplified example, but these are the kinds of discussions that the world leaders are very probably really having. Even if you're not a very humanitarian president and don't care at all about people who are not your countrymen, the big picture suggests that somebody needs to take in those refugees or everyone will suffer more for it. So essentially everyone is doing it. It's not because the world leaders are nice people. It's because they know it's the "lesser evil".

The endgame should be trying to help people live where they are. Once you have a huge number of refugees, there are no good options left.

TL;DR
Yes, some of the refugees will very likely be or become terrorists. But taking them in is STILL the lesser evil. Even if you don't actually care about the refugees.

You just have accept that it's an imperfect world, and be prepared for the likely problems.

Yes, all very interesting and hypothetical, but you still need to vet the Syrians. If security measures are not used, Canada becomes a loophole and your percentages then become much higher.