Welcome to the Summer of Slay, America.

Welcome to the blood-slicked sidewalks of summer. It’s going to be a long one. And hot.

Shootings in Gotham were running at the rate of one an hour for much of the weekend, with final numbers up in the air. Upstate, 18 people were shot in Albany, two fatally, over three days; 12 hit in Syracuse, including nine at a single party; 10 in Buffalo.

Appalling? Sure. But think of it as the first fruits of criminal-justice “reform.”

To be sure, the Empire State wasn’t unique. In Chicago, police reported 102 shootings over the Father’s Day holiday — 14 fatal, including a 3-year-old boy. But you need a mechanical clicker to keep track of Chicago, so the weekend toll is likely to be higher.

Elsewhere, 11 were reported shot, with one fatality, in both Minneapolis and Detroit — and bullets were flying around Philadelphia, Baltimore and most of the rest of urban America.

While each state is unique, it is fair to look at New York as a laboratory, with Albany’s utterly otherworldly surrender to public-safety nihilism exacerbated by timorous, low-impact policing policies ­embraced at the local level.

Whether the new ways are working depends on your perspective: If the point is to keep the anarchists and activists quiet, in a cynical sort of way, they are. But if they are meant to keep citizens safe, it’s all an ­absurd charade.

At a more molecular level, where the bloody sidewalks are, cause-and-effect rules. That is, reeling cops in from the streets so there are few collisions and nobody gets angry comes with sanguinary consequences.

Veteran cops tell me they saw the crisis coming. They blame:

• New York’s effective abolition of bail for all but the most serious offenses.
• Procedural changes that hogtie prosecutors, particularly accelerated arraignment and trial deadline.
• Local DAs deciding for themselves which crimes they’ll prosecute and which ones they won’t, especially drug offenses. This causes confusion and — among other things — all but ­invites new drug dealers into the trade.
• And the refusal of local officials to directly and graphically condemn violent crime when it occurs, which is generating a moral vacuum that encourages criminals and disheartens the law-abiding.

All this is fundamentally altering the state’s criminal-justice topography. Drug dealers seek to conquer new territories. Old-fashioned gang turf wars — think “West Side Story,” but with semi-automatic weapons — are breaking out all over. Ancient scores are being settled as warm weather sets in, and young gunmen no longer need fear packing in public.

“Two things are igniting all the shootings,” said a veteran lawman. “Gangs and the lack of fear of being stopped while carrying.”

NYPD Commissioner Dermot Shea last week made matters substantially more dangerous by dismantling the department’s tried and tested, 600-officer anti-crime unit, created in the early 1990s specifically to combat gun offenses.

“The elimination of these units is an extreme measure,” said a seasoned police executive, ­“because they were the only real crime fighters and one of the few tools a precinct commander has to fight violence.”

To be sure, increasing violence was a fact before Shea trashed the anti-crime units — but that’s largely a result of new policies designed to reduce conflict ­between police and minority communities. That is, to reduce the so-called “disparate impact” vigorous law enforcement has on those communities.

How ironic, then, that urban gun violence and its related traumas are felt almost exclusively in minority — particularly African-American — neighborhoods. Mothers in Midtown Manhattan weren’t putting their babies to bed in bathtubs to protect them from stray bullets during the crack wars, but mothers in Harlem were. Every night.

Does New York — does all of urban America — really want those days back?

The choice probably doesn’t have to be between occasional violent urban collisions involving cops and ignoring wildly unrestrained criminal violence in big cities, where perpetrators and victims almost exclusively are black or Hispanic.

But this seems to be all that’s on the table.

Frankly, cowardly nonintervention in the carnage that now wracks America’s cities seems infinitely more racist than what’s ostensibly motivating Black Lives Matter activists.

And nobody’s seriously talking about that. So maybe somebody should hold a protest.