I think I'm going to extend the bar fight of ideas a bit more. I'll move it into the D&D Tavern of ideas, because I think it's a bit better thematically.
Within any political community, there exist two fundamental questions. How is the decision making structure designed and how that structure responds to problems. A system where the bartender gets to make all decisions and whenever the bartender dies there are rules of priority to decide the next bartender. Such a system is reasonable, but utterly dependent on an effective bartender who can make good decisions as well as control the rest of the clientele.
The American system, vastly simplified, has people voting for people to vote to make decisions (the Republican system of government), but those decisions are strictly checked and balanced by our own procedural rules, most critical of which is a procedure to change the procedure. Of specific note is the fact that representatives, once in office, are free to make decisions until they're up for reelection. Unexpected problems get dealt with by the people in office, generally speaking. However, it's easy to consider running for office on the basis of "The damn TV is going to be changed to the weather channel the second I get the remote"
As such, the political dialogue is centered around us patrons arguing amongst ourselves, partially about what's procedural acceptable, but mostly about what current representatives should be doing and about what features/ who the next representatives should be doing and possessing. There's a lot that's permissible in this dialogue. You can annoy your neighbor to some extent, you can shout, you can largely lie (although there's backlash when the truth finally gets its pants on), you can even agree to go into a party with that one really creepy dude who wants to play the Cranberries on the jukebox, as long as he agrees with you on the institution of happy hour. Remember, most people just want to drink their damn drink and not be bothered, so they're ripe for convincing by hook or by crook (and the line between those two things is very shaky). In some cases, you can even swing on someone, but that's certainly going to have repercussions (equivalent to nonviolent, illegal protest in the American system, but only to certain extends and established only by our social norms).
If it comes down to it, you can bet your bottom dollar that the preponderance of force in the bar isn't going to take lightly to aggression. Sucker punching someone might be survivable, but there's things that are beyond the pale in the tavern dialogue. You don't get to stab people, and you sure as hell don't burn down the bar.
At the end of the day, procedural and direct decision have to be made somehow, and tavern brawling isn't the worst, and with the number of people and factions and social norms of America, it's almost certainly the least bad. And if it isn't? Well, that's the fault of the people in the bar. Each and every one of us is complicit in the system. Tolerate it, participate in it, or try to change the system through the procedures in place, none of them require violence.