The U.S. is in a Sub Rosa battle with these four countries. Each want to undermine the U.S. dominance economically and militarily. To that end, one way or another, world events are shaped by this battle and at some point it will affect stock prices.
These countries love to see the U.S. in political turmoil whether it be for impeachment efforts, chaos and rancor between Republicans and Democrats or the infighting inside the parties themselves. All four antagonist do their best to take advantage.
Something is likely to break this year. Iran may finally do something which the U.S. has to respond. North Korea does not seem to want to play nice with its missile testing provocations. Russia is always behind disruptions through cyber warfare and China is not far behind or may even be ahead in their efforts in that war. Trade is the current battle ground with China, but they are fighting us on many fronts.
These are all potential market moving battles.