[Saber Cherry]

Great idea!!

I would rename it to "Strategic Interception", though - took me a while to figure out what you were saying... at first I thought it was weapons being used defensively.

Another approach would be (similar to Stars!) an "Intercept" order. And army with "Intercept" commands would act just like an army on "Defend", but would automatically move to defend any adjacent province. You would not be able to set a priority, so by default, it should intercept the most lethal threat.