AFA / AntiFA, the extreme left terror organisation is going to Syria to learn warfare and build revolutionary organisation. Even though I applaud them for fighting ISIS, I cant help but find this more than a little worrying.

Yes. Some of us still remember the days when RAF and Red Brigades worked together with PFLP, PLO and whatnot. Since plane hijackings are now more difficult, we'll be seeing the left and Middle Eastern radicals working together to bomb European soft targets like concerts, markets, railway stations etc.

This reinforces my opinion that it's a good idea to restrict warfare to state actors and make it a criminal offense to join armed movements in foreign countries.

I have a lot of sympathy for Kurds in their struggle for a nation of their own, but having members of the public travel from European countries to fight for or against Daesh, be indoctrinated to kill, and then return to Europe carrying both the technical learnings of warfare, the ideological baggage collected, and the emotional trauma of war, can lead to further atrocities in Europe.

Armies of governments aren't all good and nice, but they do have more restrictions on what they can and will do, compared to ad hoc militias - and more follow-up of how former service members are doing.

Or - if you switch off the clickbait title - anarchists as the pawns in the irredentist movement spread out over four sovereign states.