Does trumps actions significantly impact the US market

For example, if trump continues with his threats and his "tactics", we could see a trade war. Countries completing cutting ties with the US. If he does act like an absolute moron (which isn't surprising) and desides he will invade Greenland, start a war in panama etc, this would absolutely obliterate the markets right? At this point I feel there's a very significant chance we see a trade war. Along with this maybe even physical conflicts.

I dont really delve into politics much, but seen as I have a significant portion of my portfolio in the ISA, it does concern me. I'm likely heavily wrong but its just nice to have this explained. Thanks anyways and any criticism of my mindset is fine. We are all learning at the end of the day.