Some observations I've made over the years.
Here are some things that cause division:
- One or more sides feel that they are not being heard
- One or more sides feel that there is favoritism
- One or more sides feel that there is cliquishness
- A breakdown in civility
Controversy only becomes a factor when those four are in play.
I'll start with the last first.
A breakdown in civility
When there is a breakdown in civility, the previous three points are amplified, because it will turn into a free-for-all, and from there, any moderation will be seen as unfair as cries of "Why did you step in NOW after he said all of that to me."
- At the first sign of incivility, step in.
- Make sure discussions are about topics, not people (see point 1).
- Have a kindness policy. If it's unkind, don't post it. (see point 1).
- Discourage "dogpiling"
One or more sides feel that they are not being heard
Encourage discussion from all sides, try to find common ground and build on that. This can make even the most heated topics turn into discussions, not fights. Be on the lookout for anyone encouraging/employing any of the following tactics
- The filibuster. Talking a topic to death to the point where others retreat
- Dogpiling... getting others to join in to deride someone's opinion.
- Swarming... burying someone's opinion in a swarm of replies from a single or multiple people
- The Columbo.... Pretending not to understand a person to frustrate them
If you see any of these, you need to step in and bring things back on topic.
One or more sides feel that there is favoritism
You need to be able to demonstrate that there is none. Be as fair as you can, step in early and try the light touch first, because sometimes people just need to say their peace.
Also, if, by the time you step in, all sides have settled down, acknowledge that they have, and just comment that you're glad that they were able to handle it (treat them like adults)
One or more sides feel that there is cliquishness
This is hard to combat because there will be regular long-time people, people who drop in and out, and new people.
All you can do is encourage mingling.
You want to be very careful in declaring certain topics "VERBOTEN", as people will quickly learn to get uncivil if they want a topic shut down.
Worse, this can become a tactic to drive people out especially when it becomes a tactic to scold people for bringing up a controversial topic.
The old standard admonition of "Please don't feed the troll" helps as well.
The best way to keep controversy from becoming an issue is to look for those who seek to make it one.
These are not necessarily those people spoiling for a fight, but rather the people who are egging others on.
ONCE YOU FIND A COMMUNITY DIVIDED
You need to crack down on the incivility first. That will stop the bleeding so to speak.
Then, you promote discussion where there is common ground. The key is to get people talking again.
After that, you will find the community cooling down a bit, and you can start to re-introduce a few hot-button topics, but enforce civility very strictly until it becomes habit