The chance of it happening are about a 50/50, Trump can bomb Iran all he want's and hes just gonna start a little war for themselves. But once Iran strikes US soil that's when NATO will step in, and if Iran escalates from there. World War 3 will be a thing.
It's very unfortunate how many lives have already been lost due to this feud.
Personally I think they should both put on their big boy pants and just call it a day.