I agree with Whirlibird, looking at the overall probabilities the long grind into poverty and collapse of the system is the most likely scenario in my opinion. That does not mean anything else that could speed this up greatly couldnt happen before.
Terrorist attacks are most likely, closely followed by natural disasters. I doubt Putin or any other totalitarian ruler will go crazy for another war. After the two last wars the US won’t fight anywhere anytime soon as well.
At the end of the day I liked what Selco said and that is to focus on your local area and be prepared for the worst case. Like Mr. Red said:
Sometimes I like to think about what the major event, or events, that will ultimately take place to put us into a big SHTF event will be, and when it’d happen. But then I realise that it’s rather pointless to have that ticking away in my mind. Whatever happens, whenever it happens, will happen, all I can do is make ready myself and my people.
Alea iacta est ("The die has been cast")