America and its leaders poking nose all over the world, that is the biggest threat to the world and US itself. They caused Ukranian dismemberment by provoking Russia. Toppled secular people like Saddam and Gaddafi letting loose the Islamist loonies. Now they want to topple Assad. They propped up rag tag militias which ended up fighting alongside AlQaeda and ISIS. The situation is so messed up that the prime competition to ISIS in Syria until a month ago was the Al-Nusra Front(Al Qaeda).