What do you think will cause the next world war?
A good example is what is happening in Syria.
Russia supports Assad, the Coalition support the Syrian rebels and are against IS.
Iran is sending fighters to support Assad, Hezbollah by proxy are supporting Assad in the south - all Shiite clans - except for Russia of course....!
Assad is reputed to have said about IS that being in Syria is not unfortunate because they are his enemy and IS are also his enemies (the US led coalition forces + Kurds etc) enemy.
So any conflict of interest, misunderstanding, misinterpretation etc etc among all these players, Iraq, Syria, Russia, Iran, Lebanon, Kurds, Turkey, US, and the US led Coalition countries, etc etc and the social upheaval that is happening because of the huge refugee crisis in Europe especially in some countries who are simply "kicking the can down the road " and some countries who are really doing something about taking them in, so there are those who are for and those who are opposed to their presence
All of this needs to be managed well because Plan A is in the development stage and no one appears to have a Plan B so if it all goes pear shaped there will be unforeseen outcomes so I hope everyone involved treads very carefully through this minefield.
Putin, and an arrogant Republican President, should we elect one. A man who says: "How could I be gangster? I was KGB!" is capable of strange reasoning and unthinkable reactions. To simply go after the man with hubris and "bravery" is a recipe for disaster!
As Einstein said: "I know not with what weapons WW3 will be fought, but WW4 will be fought with spears and stones."