After the Newtown shootings, a British journalist was heard to observe that if the killing of children was tolerable, the gun debate in the U.S. was over.

That may have changed. The killing of 5 police officers in Dallas might finally galvanize public opinion on gun control in a way that nothing has — at least for 50 years.

Dallas, of course has a fraught history with firearms. Because Lee Harvey Oswald used a mail-order rifle to kill President Kennedy, the NRA supported both banning mail-order sales of rifles and the 1968 Gun Control Act.

An illuminating article in the Atlantic Monthly, “The Secret History of Guns,” notes that the Black Panthers’ exercise of  their right to bear arms is what led to the passage of the Mulford Act in California, which repealed a law allowing public carrying of loaded firearms.

But as Mike Weisser, AKA Mike the Gun Guy, observed in an interview with The New Yorker’s Evan Osnos, the spectacle of a white motorist being beaten in L.A. following the Rodney King verdict was a defining moment in the NRA’s campaign to use fear — and racial fear —  as a way to promote gun ownership.

[See The Second Amendment’s Second-Class Citizens]

Now a black gun owner professing to want to kill white police officers is implicated in the shooting of 12 Dallas cops, five fatally. It must finally appear to its members that the NRA has opened a Pandora’s Box in much the same way the the GOP’s messaging has ultimately led to the nomination of Donald Trump. Crazy talk leads to crazy actions.

One of the painful ironies is that the Dallas Police Department appears to be one of country’s most respectful and respected. (Listen to Rev. Michael Waters speak to NPR.) And as the Falcon Heights shooting suggests, the proliferation of guns in black communities is unnerving to police.

Another irony is that the extra-judicial killing of the Dallas suspect, Micah Xavier Johnson, will likely be viewed by many as further proof that black lives don’t matter to police. I’ll personally suspend judgment as to whether the robot-delivered bomb was the only solution to the standoff, but I’m sure others won’t.

The killings in Dallas are shocking and horrifying, but aren’t we all, somewhere deep inside, a little surprised that it didn’t happen sooner?

We can expect the killings by police and of police — and vastly more frequently of American citizens by other citizens — to continue until we recognize that the proliferation of instruments designed  to kill human beings — designed to kill human beings — is morally unacceptable, and must not only be halted, but reversed.

It won’t be easy, but the alternative is simply intolerable.