What has created the environment where the U.S. and many other nations are closer to civil war?

I think there are many factors but the two most pressing ones would be:

1. Trump asking Russia's help to win the 2016 elections and then they did. And then Trump being 

delusional (or just wanting to stay president) one of the two and trying to make people believe the election was stolen. And enough people believed this that the January 6th Insurrection took place and many died or were injured, some permanently and many have and many more will go to jail because of it. "Maybe some Republican Congressmen and Senators too the way it's presently going. And Trump might have to leave the country and go to Somewhere in the Caribbean or elsewhere to avoid prosecution or conviction at this point too.

2. Covid also causes isolationism because people have to isolate in order to not die of Covid. This allows people to go way out into tangents and when you combine this with crazy social media sites you get people who are willing to grab weapons and start shooting like some of those on January 6th did mostly with clubs and knives and stun guns and bear spray and whatever they could find to throw at police.

One could also blame social media sites like Facebook but now facebook has changed it's name to limit it's liability as well in this. The problem with Facebook has always been money over "Doing what's right for the most people" and in this we have another factor in why we could be headed to civil war right now. 

However, if enough people are aware we are close to civil war it likely can be prevented for the most part because the Silent Majority want to keep our democracy intact and not turn it into a fascist State like Hitler's Germany or Italy's Mussolini.

So, the minority wanting civil war have to be stopped anyway possible at this point and if they aren't stopped then put in jail so they are made an example of for all to see worldwide.