One way for leaders to achieve increased control over their citizens would be to introduce a problem then provide a solution. If a majority of 'natives' of a country feel threatened by newcomers and have no realistic alternatives for 'protection' than the state, that's what they will choose. This could take the form of increased surveillance of society generally and an increase in the number and capabilities of state sponsored paramilitary assets.
I wonder if this is not one of the main driving forces behind the push to control guns in private hands here in the U.S. The more people feel confident that they can protect themselves, the less inclined they are to rely on the state for various kinds of protection.
As best I can tell from afar (sitting here on the West coast of the U.S.) it seems that Western Europe is a lot farther along the path to centralization and that planning and directing these population movements is handled mostly from Brussels. It's an interesting thing to watch. I'll be paying closer attention to the phenomenon.
Brussels has yet to answer to the problems of these thousands of migrants who arrive every week. Ask anyone in Italy, he'll say the EU doesn't do anything, and that is correct. It is member states, Hungary beefing up its borders, France blocking the migrants in Ventimiglia, who act, leaving all the burden to countries on the Southern side, Italy or Greece.
Regarding protection, it isn't the issue here. There's about 40 millions people unemployed in EU. Many locals just wonder what will the migrants do if they're allowed to get in? This as a time where most countries are running a deficit.
As I say, it seems to me a reasonable hypothesis that Brussels does not see the issue as a 'problem' in the way that the locals do. The hypothesis continues that the 'solution' would be a general beefing up of state controlled domestic surveillance and paramilitary capabilities which are, of course, fairly easily moved from one task to another. From what I read here across the pond it seems that this is occurring here and there. It would be counter-productive for Brussels to comment on this if they do consider it a 'solution'.