One thing’s clear about Saturday’s Buffalo massacre: Payton Gendron, 18, never should’ve been able to get his hands on the Bushmaster assault-style rifle used in the slaughter.

And authorities will never rein in such madness if they focus on merely passing laws rather than enforcing them.

Tuesday, Gov. Kathy Hochul is expected to offer steps to close loopholes in state law. Fine: Prosecutors, for example, say they must show the date of manufacture of large-scale magazines — the kind Gendron apparently used — which are illegal in New York. Yet magazines typically don’t carry that info, so perps caught with them usually can’t be prosecuted.

Still, enough laws were surely in place, and ample red flags emerged, at least to keep Gendron from possessing a Bushmaster XM assault-style rifle: He wore a full-blown hazmat suit to school and said he wanted to commit a murder-suicide after graduating. He’d been hospitalized for a mental-health evaluation for a day and half. And he posted a 180-page racist, anti-Semitic manifesto praising mass killers and exposing his own radicalization.

Yet the gun dealer who sold him the Bushmaster insisted nothing came up in the background check. Huh?

Look: If Google can know enough to target specific ads to people who merely use its search engine, the tech surely exists to let law enforcement connect the dots about Gendron.

More coverage on the Buffalo supermarket shooting

When Gov. Andrew Cuomo signed the NY Safe Act in 2013 after the Sandy Hook shooting, he called it “the toughest gun control law in the nation.” Yet it didn’t stop Gendron. Notably, that law limited magazine capacity to 10 rounds, but Gendron got a 30-round magazine and modified his Bushmaster to accommodate it.

Meanwhile, the state’s red-flag law lets judges temporarily ban possession of a firearm if presented sufficient evidence someone is a threat. Apparently, no one made any such claim about Gendron.

Fact is, with every mass shooting, there’s a rush to “toughen” laws, but officials, particularly in New York, too often fail to emphasize enforcement. Indeed, this state’s main focus recently has been on emptying jails.

Hochul herself was fine with New York’s let-’em-loose criminal-justice reforms, despite soaring crime, until pressured to make token tweaks. And she’d rather blame the feds for weapons that cross state lines than get tough with criminals caught with them.

Sure, by all means, close loopholes. But absent a serious enforcement crackdown on law-breakers — and those on their way to becoming one, as Gendron was — all the anti-gun laws in the world won’t mean a damn thing.