[PTTG]

Recently I've been working on putting together a grand campaign and drawing inspiration from Xenonauts and X-Com. If you're my players, consider not reading this thread?

In general terms, we have the invading aliens and the defending humans. Timeline is early 2018 (meaning it will probably still be in the future when the game rolls around.

I have a fairly firm mythos in terms of why the aliens are invading subtly as opposed to, say, dropping a rock or a viral swarm or just coming in guns blazing on day one.

What I don't have yet is a good background for the human (PC) organization that opposes the aliens. The Players will have two characters; one cast will be soldiers, the other cast will be the upper-echelon (scientists, engineers, commanders). They need to be global in scope, but have limited resources. They need to be seen as the unified face of humanity but have internal factions and strife to deal with.

Of course, in time the aliens are going to have more subtle plans than overt attacks or even surgical strikes- and some humans are going to see the value of changing sides...

So, my questions are:

1.) What's the best way to run a world-wide strategic game? Has anyone tried anything like this in GURPS before?

2.) How can I build info on my PC organization rules-wise?

3.) Lore-wise, what's a good way to have modern nations and organizations contribute to defend the planet from aliens?

4.) What's a good "first strike" from the alien forces? It needs to be serious encourage the world to go along with #3, it needs to be subtle enough to cover up, and it needs to ideally allow the PCs to come into play.