Perhaps the most tragic aspect of Payton Gendron’s homicidal rampage inside a Buffalo, New York, supermarket on Sunday is that it was entirely preventable.

As we’ve seen numerous times, government officials failed to use available law enforcement tools that likely would have deterred Gendron.

More on that later. First, let’s confront the smear campaign blaming people in the GOP for the tragedy.

As has been widely reported, Gendron posted a manifesto before the attack that espoused racist ideology and detailed his killing plans — which focused on black people. Eight of the 10 people he murdered were black.

The smear campaign’s main target appears to be Elise Stefanik, a Republican member of the House whose district lies in upstate New York.

On Sunday, the Washington Post published an article headlined “Stefanik echoed racist theory allegedly espoused by Buffalo suspect,” referencing the so-called “great replacement theory.”

“The baseless conspiracy theory,” the article explains, “claims that politicians are attempting to wipe out White Americans and their influence by replacing them with non-White immigrants.”

The Post certainly knows something about conspiracy theories, being one of the many media outlets which helped spread the Russia collusion hoax that did so much damage to the country.

Stefanik, the article concedes, has never mentioned the replacement theory. But “she and other conservatives have echoed [its] tenants,” it claims, “as part of anti-immigrant rhetoric that has fired up the Republican base.”

The real issue is that for left-wing journalists like Marianna Sotomayor, the article’s author, anyone who complains about President Joe Biden’s abject failure to carry out his constitutional duty to enforce the nation’s immigration laws is guilty of xenophobia.

Besides, what animates the racial views of people like Gendron is that like, say, Planned Parenthood founder Margaret Sanger, they believe that blacks and other minority groups are inherently inferior.

And regarding the GOP’s concerns that Democrats see illegal immigration as politically beneficial, it’s not exactly a secret that Democrats have long dreamt of achieving permanent electoral majorities due to changing demographics.

Liberals have also been carpet-bombing Republicans since Sunday for inaction on gun control.

After the massacre, Buffalo’s Democratic mayor, Byron Brown, complained that gun control measures are blocked by “some on one side of the aisle.”

Here’s a newsflash, Mayor Brown: New York has a mechanism that could have, and likely would have, prevented Sunday’s massacre: an Extreme Risk Protection Order (ERPO) under Article 63A.

Under this section, also called New York’s red flag law, a court may prohibit someone from purchasing or possessing a firearm for up to one year if he or she is shown to be a risk.

Police, district attorneys, family members, and school administrators can all apply for ERPOs, under which police can also remove any firearms owned or possessed by the individual.

Sadly, state police; local cops in Conklin, New York, where Gendron lived; and administrators at Susquehanna Valley High School, where he graduated last year, all dropped the ball by failing to do so.

According to news reports, a concerned person contacted state police in June of 2021, terrified that Gendron was “threatening to shoot up graduation-related events.”

Reports also indicate that when asked about his post-graduation plans, Gendron, who classmates say wore a full hazmat suit to school due to COVID fears, replied “murder-suicide.”

Progressives shuttered the country’s psychiatric hospitals years ago during their deinstitutionalization crusade, and involuntary commitment laws often make it difficult to hold someone for more than a few days in what limited spaces are available — which may explain why Gendron was released one day after cops brought him to a hospital for an evaluation based on these threats.

But this still doesn’t explain the failure to obtain an ERPO — which would have prevented Gendron from purchasing the semiautomatic rifle he reportedly used.

Under Article 63A, state officials must immediately report the ERPO to the FBI, which uploads it into the NICS background check system — blocking firearm sales to the named person.

It’s not clear whether state or local police contacted the FBI last June when Gendron was threatening to shoot up graduation events and commit murder-suicide. If not, why not?

The agency would have been able to secure a warrant to search Gendron’s computer and cellphones. And knowing that he was the subject of a federal investigation may have altered Gendron’s plans.

Also inexcusable is authorities’ apparent failure to charge Gendron with making a terroristic threat under Section 490.20 of the New York penal code, a class D felony. Having some consequence or being subject to some kind of juvenile court oversight (his threats were made days before turning 18) may also have altered his trajectory.

The state police sought to justify its inaction by noting that Gendron’s threats didn’t name or target specific individuals. But that’s ridiculous. By their nature, threats to kill large numbers of people don’t name specific individuals.

The press seems incredibly deferential regarding the inaction of New York officials. The reason should be obvious: portraying America as systemically racist and blaming Republicans for Gendron’s individual act of terror better fits the Democrat narrative.

Ken Sondik, an attorney in Zionsville, Indiana, can be reached at kensondik@sondiklaw.com.