How do you determine which is right?

Why, you look at what France and other European countries did. We know that whatever they did led to Paris and Brussels. Do you think they radicalized the Muslims by heavy-handed patrolling of Muslim neighbourhoods and being generally oppressive toward them? Or did the European policy involve averting their eyes and issuing proclamations about how Muslims should feel welcome (the term "appeasement" isn't terribly popular)?

Are you assuming they're mutually exclusive? Why?

Would you consider it to hard on Muslims or soft on Muslims if France would head the call of it's Muslim community to require Imam's to have a license to preach?

Our soft response to terrorism compared to, say, how Saudi Arabia deals with terrorists who threaten it,

Saudi Arabia pays the terrorists to move their operations to other countries. That isn't exactly being soft on terrorism.

I hear you, but I don't think the theories are opposite to each other.

Let's take them one at a time. First, would you agree that angry rhetoric, intimidation and surveillance contributes to ISIS getting more recruits? If so, then it's a true statement, independent of the other statement.

Regarding the second, I'm not sure the word "soft" is warranted here, as it prejudges the question in advance. The question you seem to be asking is whether our current response to terrorists signals that the West is weak and thus does not provide sufficient disincentives to terrorists. When using the word terrorists, it seems that you are speaking about the people carrying out the acts. Those people generally are prepared to die - many are either suicide bombers, or make suicide-style attacks expecting to die. Thus, using tactics such as police surveillance of neighborhoods as Cruz proposed is unlikely to provide a disincentive at all. Heck, even jailing them for life will not, or taking 10 years to kill them as our current death penalty laws stand.

Now, I can try to steelman the second theory, and talk about the people behind the suicide bombers, those who incite them - so not terrorists themselves, but ideological leaders. Having police patrol Muslim neighborhoods will do nothing to deter ideological leaders, natch - they are the radical imams in mosques, the bloggers on the internet, etc. So my point still stands on Cruz's solution being, to say it mildly, unhelpful.

Can we do something about the radical imams? Sure! However, this is not a topic I chose to focus on in the article, and I haven't given it sufficient consideration to make a strong and clear statement about it. I'd welcome thoughts from LWs about what can be done.