I have a question primarily dealing with the secondary ability of the Diplomacy II strategy card from SE. The secondary ability allows annexation of a planet adjacent to a system you control. I'm curious as to whether this definition of control is as strict as that mentioned on the objective cards, as this seems to be the only place I can find any definition at all. So the question is, when peacefully annexing a planet, does the system containing the planet to be annexed have to be adjacent to a system that you a) Have capital ships in, and b) control every planet?

a) and b) yes. You are correct, you must control all the planets and control the space to annex adjacent planets. This is quite nice if you failied to land a planet in a multi-planet system adjacent to your home system or to grab a power system just outside of your reach first turn. If you use territorial distant suns, this is a good way to avoid tripping things like radiation or PDSs.

It's worth noting that to control a 0-planet system, all you need is a ship. You control all 0 planets, and control the space.

Thanks for the clarification, guys.

I too concur.

Thanks for the response Pscilone.