The US engaged in a direct act of war with the Syrian government, as it deliberately shot down a Syrian government jet.
http://www.smh.com.au/world/us-warplane-shoots-down-syrian-jet-20170618-gwtqcl.html
The US similarly attacked and destroyed the Libyan air force prior to the overthrow of Qaddafi, so this act has serious implications for the Assad regime. Russia fully understands this.
The US is directly responsible for the chaos engulfing a quarter of the world, as it continues to make war on the enemies of Israel. Should they succeed in bringing down Assad, the result will be same as in Afghanistan, Libya, and Iraq — ongoing societal chaos.
When the Seventh Seal is opened, I believe that it will be the actions of the US that leads to the nuclear war that is implied in the prophecies of Revelation. Should the Yellowstone caldera actually erupt, perhaps one could argue that it is ‘karma’ given that America unleashed Death and Hades on a quarter of the world.