I absolutely love your bit about why we would fare so poorly in a fight against any alien civilization. I had never considered it that way before, but you're absolutely right. Any alien species with FTL travel could kill every single one of us with remarkable ease, whether or not they had any conventional weapons or armies. I vote we begin immediate plans to build an Interplanetary Projectile Defense Network that will destroy anything moving toward us.

I think that given the right conditions of cumulative self-interest, the world could form something approximating a unified global government. But you make a compelling case for why those conditions are unlikely to form.

If humans expand our space-ward business, do you think that eventual inter-planetary efforts would be joint efforts where nations worked together and split the benefit, or do you think nations would are more likely to try to do things on their own?

Do you think that the colonization of space (whether of constructed habitats or of actual worlds) would be similar to the European colonization of other parts of the world, with each involved nation carving out its own piece and using it to increase its economic power, and as bargaining chips in negotiations back home? This leads me to wonder — if other worlds/habitations were originally populated by people of a similar cultural background (ie. all westerners, or all Chinese), and then if those worlds/habitations eventually secured self-rule, might it be possible that other worlds/habitations would stand a better chance at achieving a unified global sort of government than Earth itself does?