There's a winning strategy in iterated games theory (I think).

1. Never strike first
2. Tit for tat escalation. Each time the opponent attacks, attack back
3. Immediately back down when the opponent backs down
4. Offer negotiation at every stage

This looks like what Iran is doing. The problem arises when the initial aggressor thinks they are all powerful and believes they have an undeniable right to win.

@jbond The issue isn't just that they think they have the right to win, they didn't decide on what winning was ahead of time. Killing the people you're supposed to negotiate with doesn't help either.