Orks are fundamentally a might-makes-right society. You might be able to work out a rough fascimile of some sort of government, but it'd never get more complicated than different tribes/bands choosing a representative via brawling with each other to create a 'council' of Bosses who'd then brawl with each other to pick a Head Boss/Warboss, dispatching orders back down the chain and brawling instead of debating to settle disagreements. On the other hand, that's a sort of 'guvviment' that might actually be capable of being sold as Orky, if it's presented enough like a sort of arena/tournament style of mob rule...the trickiest bit would be convincing them that they gotta challenge their Boss before they can challenge the Warboss or Head Boss, and skipping the krumpin' chain of command is cheatin'. And you'll never get anything like an organized police force...if an Ork can't settle his problems himself, he's not worthy of being an Ork.