User blog comment:Yellowwinx8/Justice League vs. Rimbor/@comment-34954086-20121008012309/@comment-34954086-20121008082842

Oh, in that case:

The Guardians encourage a trial involving such proven law enforcers as an opportunity to have the planet excised of it's criminal element (READ: pretty much all of it) and make itself safer. By having them sent instead of their own forces, they don't have to contribute as many of their forces (basically only lanterns on par with the League members'd be the uber Lanterns who they have close to Oa, which serve primarily to guard them from attack) and can maintain well guarded while managing to take the planet.