Adult dogs correct each other, and they correct puppies. A stare, a lifted lip, a body block, a brief warning nip. The other dog adjusts and stays adjusted. This is documented ethology, in Bekoff's work on play and fair play and in Bradshaw and colleagues' work on domestic dogs, not pack theory. Pack theory's mistake was the conclusion it drew, that the human should be in charge and that problems are status-seeking. Drop the conclusion; the observation stands.
Call the mechanism what it is. Something unpleasant appears and the behaviour stops: that is positive punishment, and it is the channel dogs use with each other every day. Discomfort as information is native to how they communicate. The positive approach asks the owner to be the only being in the dog's life who never uses it. Even its own puppy advice, socialise with well-mannered adult dogs, hands the job to dogs who do it well.
The only guardrail is proportionality, not mechanism. A warning nip is not a fight. The dog's correction is proportionate, instant, and over the moment the other dog yields, and that is the standard every human tool should be held to. The dog's own ladder, a look, a lip lift, a growl, a snap, is the least-intrusive principle in fur. This page endorses that principle. Here it is, written by dogs.