William Bratton is leaving the NYPD. What will his legacy be?

There are two William Brattons, and Billy Blanco knows both of them.

Bratton is the police commissioner who will ride into the sunset this afternoon, his legacy sharply debated. Champions say he saved New York City. Critics say his philosophies only divided it along racial lines.

Blanco, 43, is a Bronx native and former construction worker prone to seizures, now homeless and living with his dog; a regular New Yorker, like many others he struggles to describe the legacy of this Boston transplant who has so deeply affected New York.

On the one hand…

Blanco has seen the fallout from Bratton’s focus on the small things up close. A representative sample:

A few months ago, Billy Blanco and his dog were riding a downtown 6 train. It was 2 p.m.; the train was nearly empty. Blanco sat quietly on the seat. His brown-furred pitbull Ted did, too. The dog was on a leash.

Then, two police officers came by and started giving him the business. No dogs allowed on the subway, they said. But it’s a service dog, Blanco claimed, for his seizures. Where’s the dog’s ID? He didn’t have one.

The cops told him to get off the train. So he did. Then got on the next one.

Or there was the time he says he got hit by a car, and a cop wrote him a ticket for jaywalking when he tried to report it.

Or the times he went to jail for things like open container violations. “Little nonsense.” See the judge, time-served.

But even with these experiences, he finds Bratton’s guiding philosophy hard to dismiss. Bratton’s broken-windows and quality-of-life focus makes some innate sense, goes this argument — if you do one thing wrong, you’re likely to do two.

If you’re the kind of guy who can’t borrow or beg $3 for the subway fare, “You’re clearly not doing the right thing in life,” Blanco says. Guys like that, cops will run their names and “nine times out of ten” find a warrant for arrest.

Do statistics or rigorous studies back this perception up? Not decisively, though there are conflicting claims. So like many New Yorkers, Blanco turns to something that can be readily seen: Crime has plummeted since the crack epidemic in the 80s. The results seem undeniable. Maybe Bratton had something to do with that.

Consensus on Bratton won’t come soon

We’ve been arguing about Bratton’s effectiveness for the past 20 years, and the end to that argument is nowhere in sight.

Bratton, for his part, is not slinking away in shame but leaving in fighting mode, defending the focus on small offenses and so-called “precision policing” that have made him loved and hated.

“The basic thing that police do is to maintain order,” he said this week in an appearance at the Citizens Crime Commission. “And the advocates out there that want to do away with broken windows and do away with order maintenance, that feel that they can totally do away with stop-question-and-frisk, they’re crazy. They’re out of their mind. Because that is the basic mission of the police.”

Those “advocates” are indeed questioning that “basic mission” — the role that police play in maintaining said order.

Is the best way to keep the subway clean by arresting vagrants who will inevitably return, or hiring MTA maintenance workers and focusing on supportive housing?

When quality-of-life issues rise above the level that New Yorkers can resolve amongst themselves — as inevitably happens — how do we deal with those problems? What about in potentially dangerous situations, as happened Thursday afternoon, when a man with a large knife was shot dead by officers in Midtown, after an off-duty officer tried to apprehend him and was slashed, according to police? When to shoot and when not to?

What about a different case, when the “problem” is a man selling loosie cigarettes. Do you take him down with a chokehold in order to haul him off to jail?

It was that situation that led to the death of Eric Garner, whose birthday would have been this week, but whose death fueled protests and a movement here in New York and around the country. That movement led to questioning — in a way that finally went mainstream — the business-as-usual of NYC policing that New Yorkers had become so used to over the past 20 years.

So when Bratton has his ceremonial walkout this afternoon, applauded by hundreds of cops, he will also be greeted by protesters outside 1 Police Plaza.

Bratton will then be gone; Blanco — and the continued struggle for Bratton’s legacy — will still be here.