Actually this particular war has not been in the plans for very long. I think about three weeks? I'm not sure exactly.
It's certainly been contemplated before, actually almost happened before, but this is the first it's been seriously considered for quite a while.
Even with the "most likely" war happening soon, your war is still possible to wage now. In fact, it would probably be the VERY best time to do it. No allies, no enemies, just a good o'l 1 vs 1.