“One Nation Under Dog” is an awfully cheeky, punny title considering the nature and tone of the next HBO documentary — especially when you get past the colon to “Stories of Fear, Loss & Betrayal.”

Although positioned as a piece of advocacy, the 73-minute doc, which premieres June 18, suffers from a Onenationunderdog04lack of focus, dealing with different but mostly unrelated strands of the pet-owner relationship, as well as abuse and euthanasia, which is presented in unflinching, gut-churning fashion.

Based on a book by Michael Schaffer, and produced by Ellen Goosenberg Kent, part one focuses on pet attacks, and particularly the impact of one such incident in a small community. The second section deals with people who struggle to say goodbye to their dogs when they die — been there, done that — before getting to the centerpiece, which involves pet overpopulation, gassing unwanted dogs and the horrors of puppy mills.

If it was all intended to make me feel lousy, mission accomplished. But aside from urging people to spay and neuter their pets — and demonstrating that a lot of people are irresponsible assholes when it comes to dogs — it’s diffcult to find a coherent point. Frankly, seeing the terrible manner in which dogs are put to death doesn’t do much to resolve the problems, particularly since the message is unlikely to reach those who most need to hear it.

HBO’s documentaries are often characterized by passion and a willingness to show imagery from which other news outlets shy away.

“One Nation Under Dog” certainly does all that, but in the process let its heart race ahead of its head. The project didn’t need to be leashed, exactly; just curbed.