My impression is that the United Planets Superwatch, despite its name, is more of a universal force, rather than a galactic force. Circumstantial evidence:
- Vartox is canonically from another galaxy.
- Having all those Superman clones crammed into one galaxy would really mess with the balance of power.
- The United, thus far, appear to be drawn from Milky Way races, which makes sense, as the United Planets has typically been a galactic organization:
- Psions
- Khunds
- Tamarians
- Thanagarians
- Dominators
In fact, at least three of them are drawn from the same star system (Vega), which seems to be a little over-represented