The Panel

Sometimes it is better to have a balance of views by having several speakers with different opinions. On the other hand, sometimes that makes it worse because it will create a clash between speakers, or between their groups of supporters.

If you are having speakers who are opponents, you can stage manage the discussion similar to the way news presenters do. Have a chairperson who doesn't just sit back and let them engage with each other directly. Speak between them, and direct specific questions to each of them. See the Moderator Technique. This helps more than you might think to keep the atmosphere calm and prevent people verbally attacking each other.

You could have a skilful person you trust give a short talk beforehand, gently setting the stage for how you want the event to be, setting out some ground-rules or your essential principles you want observed or your boundaries.

Then you could have this person give a response afterwards to take the temperature down. Do this in a neutral way, not rubbishing or arguing with the speaker which would only jack up the tension.

It's a good idea to have your exit strategy in mind: make sure you have designed a clear-cut end to the event. Consider having it not just end at a certain time, in case your chair or moderator needs to cut short a situation that is getting out of control. Consider instead ending with a change of activity, maybe involving a change of room, such as a reception, refreshments or prayer time; so people are redirected into something less emotive.