The world will go on, but democracy wont do just fine. Once they are done with the US they’ll push harder than ever to do the same to the EU, and they’ve already come damn close in both France and Germany. Its just a matter of time until one of them slips. And worse, without the US leading the “free world” theres a huge power vacuum/imbalance that will almost certainly have to be resolved violently, either with a spate of serious regional wars or another big global brawl.