[astrodust]

The military and certain branches of the government (e.g. CIA) are very interested in having modular, autonomous structures that can survive in the event of a decapitation attack, or if communications are severely disrupted through other means.

They're also interested in having centralized control so the various components of their organization are not running rampant and in conflict with the others.

It's a delicate balancing act. Look at the US as a whole: If states are too independent they might get into wars with the others, not unlike The Holy Roman Empire. If they're too much under the thumb of the Federal government they'll feel oppressed.