The United Federation of Planets has Starfleet. From what I can remember, the Klingons, Romulans, and Cardassians have been rivals to Starfleet. I'm leaving out the Borg and Dominion as they're from other parts of the galaxy. Were there other "equals" to the Federation, or was it mostly just these three? I was thinking, the Federation is several hundred worlds, but not necessarily solar systems. This can include multiple worlds and moons in one solar system, still that's a lot of solar systems at the very least. Anyway, Starfleet must get spread pretty thin to protect all of this. Klingons, Romulans, Cardassians, and whoever else probably have far fewer worlds by comparison, allowing them to be more concentrated with what they do with their fleets. Then you have Starfleet potentially dealing with all 3 or more at the same time. No wonder the Enterprise never has any backup.
On the "space maps," Klingon and Romulan space looks almost as big as the Federation. Then we learn the one star going supernova and taking out Romulus collapsed the entire empire. It's like Earth being destroyed and no more Federation instead of Vulcan just becoming the new capital. Kind'a bonkers, no?
So, Treksperts, just how big are the Federation's rivals, or do they just have fewer worlds to protect, allowing more ships to go offense?

On the "space maps," Klingon and Romulan space looks almost as big as the Federation. Then we learn the one star going supernova and taking out Romulus collapsed the entire empire. It's like Earth being destroyed and no more Federation instead of Vulcan just becoming the new capital. Kind'a bonkers, no?
So, Treksperts, just how big are the Federation's rivals, or do they just have fewer worlds to protect, allowing more ships to go offense?