Let's say there is a law against walking your dog without a leash on, because it will prevent unruly dogs from scaring other people out in the public(even if the dogs intent is good, people may not understand this), or staring dog fights, or pooping where they shouldn't. Sounds good.
Now, what if someone has a perfectly trained dog, that will stay right at their owners side no matter what circumstance is presented, and that dog is walking without a leash on? Is it appropriate to give that person a ticket? They are breaking the letter of the law, but the intent of the law was not broken because of how well trained the dog is.
> Let's say there is a law against walking your dog without a leash on .... Is it appropriate to give that person a ticket
Yes, because that law was written for the convenience of law enforcement. The law should have been "You need to be able to control your dog at all times when in public, with a leach if necessary", or indeed, not there at all: There are plenty of laws on the books that penalises behaviour that hurts other people. But enforcing that is a lot more difficult than determining the absence of a leach and writing a ticket, regardless of whatever harm or risk is present in the actual situation.
You're suggesting that laws should be enforced in accordance with how they should have been written, not how they are written - and while obviously a good thing in this case, it also applies in the other direction: A policer officer might feel very strongly that beating unruly arrestees is what the law should be.
Rule of law means the laws are enforced as they are written, equally for everyone, not subject to the whims of law enforcement. Making stupid laws that implicitly demands law enforcement to be arbitrary is deeply corroding to the rule of law.
If you pass laws that have faults then rely on enforcement discretion to produce justice, that puts a lot of weight on the enforcers' shoulders.
Imagine being a cop who pulls over a poor black janitor for DUI. You know last week your colleague pulled over a rich white senator who was on his way home from the police union's fundraising ball, and let him off with a caution. If you arrest the janitor your department will look like a bunch of corrupt, racist, classists. And if you don't arrest any DUIs, all the problems caused by drunk driving will get laid at your department's doorstep.
Perhaps instead of passing laws that have faults then using enforcement discretion to work around those faults, instead we should improve the laws to be fault-free. (admittedly that might need a faster release and testing cycle than we have at the moment)
Now, what if someone has a perfectly trained dog, that will stay right at their owners side no matter what circumstance is presented, and that dog is walking without a leash on? Is it appropriate to give that person a ticket? They are breaking the letter of the law, but the intent of the law was not broken because of how well trained the dog is.