Require more than two parties, and have proportional representation.
If team "east side" and team "west side" are butting up against each other with the hope of the 50%±1 of the population behind them all being on their side, but suddenly one or both of them has to face factions behind them splitting off — well, it's like how often the US Democrats are upset about the US Green Party "splitting the vote" (do US Republicans have the same reaction to the Libertarians? Libertarians barely get in the news here on the other side of the Atlantic).
I think that without proportional representation, that just pushes the half-way point further from the new party. Can anyone who has actually studied this confirm or refute? I'm in danger of LARPing XKCD here: https://xkcd.com/793/
If team "east side" and team "west side" are butting up against each other with the hope of the 50%±1 of the population behind them all being on their side, but suddenly one or both of them has to face factions behind them splitting off — well, it's like how often the US Democrats are upset about the US Green Party "splitting the vote" (do US Republicans have the same reaction to the Libertarians? Libertarians barely get in the news here on the other side of the Atlantic).
I think that without proportional representation, that just pushes the half-way point further from the new party. Can anyone who has actually studied this confirm or refute? I'm in danger of LARPing XKCD here: https://xkcd.com/793/
Then there's sortition. I'm intrigued, but have no opinion on how good it would be: https://en.wikipedia.org/wiki/Sortition