The Guardians of the Universe are a DC Comics outfit; they’re the high-handed blue-skinned hobbits who run the Green Lantern Corps from their home base on Oa (whenever it’s not being destroyed). The more modestly-titled Guardians of the Galaxy are a Marvel Comics outfit; they’re a bunch of superheroes from their future, their powers the result of adaptation to different planetary environments.
Yet I’m pretty sure I remember a DC story from the 70s (I have the vague feeling that it might have been this Superman novel, though if so, Maggin really ought to have known better) in which the blue Oan dudes were called, and in which the plot in fact turned on their being, the Guardians of the Galaxy; the villains somehow separated a chunk of the Milky Way from the rest of the galaxy (pretty powerful villains, I guess; who they were I forget), resulting in the legalistic silliness that it was no longer part of the galaxy and so no longer under the Oans’ jurisdiction.
That’s a mistake, of course; but on the other hand, the Corps doesn’t seem to concern itself much with affairs outside this galaxy. Well, how do you guard the whole universe with only a few thousand employees?
In unrelated news, did those watching Bionic Woman last night notice that the show playing on the television when Jaime enters the room was Galactica?