>>/54224/
So what's this client empire?
Traditionally an empire conquers and annexes new clay to grow. But not always. Even Rome had some Greek polities as clients in Hellas. Before incorporating them into the empire, but still. The British colonial empire was similar to this important to note: clients aren't colonies, they organized new states subordinated to Great Britain, instead of annexing them. Another example is the contemporary Franceafrique.
A client is not simply a tributary, who pays tax to their bully. A client's regime regime =/= leadership, regime is the system, the people running it can and do change consciously agrees to be subjected to the surveillance of the patron, who gives them advice, helps keeping the regime in power through maintenance and if necessary intervention. Important to note: clients don't have to follow the advice, tho the patron might pressure them into doing how they were told. In the British colonial empire there wasn't any choice, there were officials - I think the Brits called them "inspectors" - whom when they said something it was expected the colony to obey.
What the patron gets in return? In Realpolitik terms the patron state gets to raise power and security, the two things it concerns with. Essentially clients help the US to project her power all over the globe. If we view it in more liberal sense, then we can say the US state does what a state should: create opportunities for its citizens and the companies of the citizens all over the world, it ensures that they can conduct their business safe and free. The patron expects the client to keep the patron's interests in mind.
The patron relies on the clients, draw on their resources, be it economical, political, or militarily. Of course it is often not granted (just as listening to the advice), but they always can get an open door and mind to negotiate. The US relies on the clients to get aid to other clients, or use them as a proxy force in conflicts, or to bully enemies with embargo, or strengthening Washington's voice in questions of international politics.
I think we can describe the position of a client as closer than an ally, but farther than a colony. And this is to that particular one way surveillance the patron does, the client has nothing similar to that.

picrel
French foreign legion embarks to intervene in Zaire in 1978. The US had barely anything to do with the conflict, according to the book:
> Morocco stepped into the breach, sending a 1,500-man paratroop brigade, assisted by Egyptian pilots and mechanics, paid for by Saudi Arabia, and flown in by France, which added additional weapons and paramilitary advisers.