When you first get into the space stage in Spore, your homeworld has some missions for you to carry out. One of them, "It's time to go to war with another empire", often seems to be impossible to start. When you click it, you will be told that "it looks like it is not possible". This is despite the fact that I am not currently at war with any other empire, and I do have empires near my homeworld who dislike me.
What factors determine whether this mission can be taken, and once you get the answer "it looks like it is not possible", is it impossible to start the mission from then on? Nothing I do seems to allow me to start it.
Best Answer
You will be unable to do this mission if there aren't any empires you don't have an alliance with near your home world. If you've eradicated all nearby empires, but still have an empty system nearby, dropping some life forms and a monolith there will create a suitable target. If there aren't any unoccupied system, you can always destroy your colonies in a system and do the above.