For me, it comes down to a breed history of aggression and the size to seriously harm a human. Any animal that meets both of those qualities should be treated like an exotic cat and require a license, special enclosures, and extra proof of insurance to cover incidents. That way, owners who want to properly train their animals and take the time to do it right can still own those kinds of dogs, while those who just want a mean dog won't go through the effort to get the license and prove they can contain the animal.

I think by putting a size requirement in, it removes the little punt dogs (sorry punt dog owners!) from unnecessary regulation. Yes, a chihuahua can be very aggressive and snappy, but I can knock it for a loop with a well placed kick and end any threat from it if I felt I needed to do so to protect myself. I can't do the same with a PB, Rott, etc. so they SHOULD be treated differently than chihuahuas and such.

For every owner of an aggressive breed who says "my dogs would never hurt a fly and it is just the other bad owners who give the breed a bad name", I can show you a news story from a family whose well socialized pet "would have never hurt a fly" right up until it ripped the toddler's face off because the kid grabbed the wrong toy. We should just treat them like the dangerous animals that they are and make the owners accountable. When the animal is out of it's enclosure, it is on a leash and under the control of the owner...period. And if you have special insurance just to cover the animal, you can properly hold the owner financially accountable for failing to control the animal.

(Edit: I just read the last paragraph again, and wanted to make clear, I am am not trying to take a shot at responsible breeders like NeuroRN with that statement. What I mean is that there are a ton of folks out there that confuse having a well trained dog with having a dog that is no longer dangerous. Just because it is well trained and well socialized doesn't mean it is not dangerous. NeuroRN's post shows clear recognition of that and wasn't what I was talking about with that statement.)

I use a gentle lead collar and it works great on my lab. ALL dogs should be leashed while in public, even service dogs or specially trained dogs because no one knows what's going on inside an animals head.

Oh my goodness, I agree. Most people don't need to own dust bunnies much less a large dog!