Between homelessness, classroom disorder and rising crime, it might seem like there is plenty for the City Council to do. But instead of dealing with such humdrum matters, the council’s tackling the threat of nuclear war — by reaffirming New York’s status as a nuclear weapons-free zone, and setting up a commission to oversee compliance with that directive.

A hearing this week took on nuclear disarmament directly. Danny Dromm sponsored legislation to create an “advisory committee to examine nuclear disarmament and issues related to recognizing and reaffirming New York City as a nuclear-weapons-free zone.” This, in a city that has zero nuclear weapons — or even military bases.

Many New Yorkers may not know, but will surely be relieved to learn, that the city has banned the “production, transport, storage, placement or deployment of nuclear weapons” since the passage of a resolution in April 1983, at the height of the Reagan-era “No Nukes” movement.

Four decades later, the city wants to launch a committee of six members, led by the commissioner of the Mayor’s Office on International Affairs, to “establish a working definition for how a nuclear-weapons-free zone might be defined in New York” and to “host discussions, public programs and other educational initiatives related to nuclear disarmament.”

The hearing quickly ran into difficulty when Commissioner Penny Abeywardena, though agreeing with the peacenik principle, insisted that the responsibility didn’t fall under the ambit of her office, which is focused on relations with the United Nations — mostly, public relations and handling parking-ticket complaints from scofflaw consulates.

“The presence of nuclear weapons in New York City,” she clarified, “is not an international issue.” Moreover, since the deployment and use of nuclear weapons is a federal matter, “cities do not have jurisdiction or involvement in this decision-making process.”

She was right: Not only does her tiny office lack the expertise or jurisdiction to deal with the deployment of nuclear weapons, but the City Council itself has no authority over the issue, either.

But don’t tell that to the members, whose sense of mission and self-importance is global — and total. Councilman Fernando Cabrera ­argued that there is no topic that should be considered beyond the expertise of any member of city government. “That’s the whole point of having a task force,” he explained. “Very easily, you could hire somebody … a chair, a vice-chair … I just don’t see where it hurts.”

Dromm countered Abeywardena’s objections by pointing out that no one “could survive a nuclear attack on New York City” and that therefore his proposed legislation is properly an international issue. Frustrated about the lack of preparedness by the de Blasio administration, Dromm grew irate when Abeywardena couldn’t cite the number of countries that have joined the International Campaign to Abolish Nuclear Weapons. “This is a big issue in the United Nations! Again, I am surprised you have come unprepared with that number: It’s over 100 countries.” Abeywardena nodded sympathetically.

Next, Councilman Ydanis Rodriguez, now running for Congress, implored Abeywardena to observe the faces of the audience, “the thousands of years of people advocating for peace, people organizing against nuclear weapons … against a war for oil.” He continued, in an apparent reference to President Trump: “This time around, this guy who no doubt is crazy, disseminating fear in the nation by declaring war on Iran, and put [sic] the whole city, the whole nation, in danger.”

Rodriguez expressed disappointment with New York City’s political leadership for dropping the ball on keeping nuclear weapons out of the five boroughs. “This conversation is not happening in the Midwest … Mayor de Blasio was part of the solidarity movement with the Sandinistas in Nicaragua, was part of the movement organizing against nuclear weapons, so who will do this?”

Given Hizzoner’s lifelong commitment to socialist revolution, it is a little surprising that he hasn’t gotten foursquare behind this legislation. Then again, he usually only gets ­excited about radical measures for which he sees direct benefit for him or his immediate family. In any case, it’s refreshing whenever we see de Blasio or his surrogates call out ­political grandstanding for its manifest absurdity; but it is sobering to think that one day we may look back and see him as the grown-up in a city government full of toddlers.

Seth Barron is associate editor of City Journal. Twitter: @SethBarronNYC