I like this ! I can think of at least three different ways to answer this prompt, because each of my three current settings will have a very different response.
Your idea of bringing a third party into a conflict situation is fascinating ! It's very Orwellian - "We're at war with Eurasia; we've always been at war with Eurasia" kind of vibes as the pattern of alliances shifts on a regular basis.
I might have to write a response of my own to this one, although it might be a few days before I get the chance !