[JPhillips]

IMO, the best scenario is that both parties follow norms. This is far and away my preference.

The second best scenario is that neither parties follows norms. It's bad, but has the potential to end in a MAD stalemate where both parties legally enshrine some norms and decide to honor others.

The worst scenario is one side honoring norms while the other ignores them. There's no end game for that scenario. There's no point to ever surrender because they can just wait until they are in power again knowing that the other party won't do much of anything to hinder their long-term plans.