1. Let your victim ask for mercy. If your backstab victim asks you to re-ally, and it seems like a credible offer…take them up on it! In general, in Diplomacy, it is to your advantage to let rival players think your ideas are actually their ideas. Create a press environment where it seems like they have few options—and then wait to see if they ask you.
2. Say your stab was a mistake, or that you regret stabbing. Some players will admit that backstabbing them was a smart move…but not many. They’ll warn you how you’ll come to regret the backstab, that someone else will benefit much more than you, you’ll lose to someone else’s solo, etc. If your victim starts talking like that…why not agree? Agree that your stab was a mistake, and say that you regret attacking them. Ask your victim what they would like you to do to re-form the alliance. Don’t offer them everything or the offer will not be credible.
3. Find out if they will become your Janissary. In Diplomacy jargon, a “janissary” is a half-destroyed power that becomes the puppet of a stronger power in return for extra turns of life. This is a common strategy, so both of you could credibly agree that your former ally will now be your janissary. Then abuse your janissary's servility to set them up for a second stab!
4. Show your rival that there is no alternative. Oftentimes, your now-betrayed ally is facing multiple enemies at once and/or has committed all their forces to a different theater of war. Show them how they have little to lose. If they pull back to fight you, they’ll lose ground everywhere else and die slowly. If they stay the course and you stab again, they’ll die quickly. But if they stay the course and you don’t stab again, then they might do O.K.
Next time, I will discuss some methods for protecting yourself against a double backstab. Thanks for reading! —BrotherBored