My daughter got the email around 11:00 am yesterday. Don’t show up on Monday as school will be closed. The plan had been to show up Monday and Tuesday, which had already been designated as “professional development” days to prepare for the likelihood of school closings. The idea, last week, was that schools needed to figure out how they were going to deal with closing, whether they could teach remotely and how to accomplish it. For public school students, the issues are very different than college or graduate school. Think first graders.

But then, a decision was made, and that was that.

“I understand the gravity of this action and what it means for every community in our county, as well as for the families and caretakers of our students, especially health care workers with kids in school,” Nassau County Executive Laura Curran said.

Nevertheless, she said, closing the schools “is the right thing to do to protect our students, teachers, school workers and family members, parents and grandparents.”

Curran called the move “one of the last steps” to try and slow the spread of COVID-19.

Closing schools is a huge step. Not only does it mean that students will go without a period of education, but it percolates throughout their families and the economy. Students in need of support services won’t receive them. Students whose only decent meal per day is at school will go hungry. The parent, now forced to stay home, who struggled to afford to feed them before will now earn nothing. For those who believe that government checks will magically show up in their mailbox to fill the gap, that’s not how it works.

But if this was a problem on Long Island, consider the problem with New York City.

As of Sunday morning, the mayor wasn’t ready to make the call to shut down the school system.

“My blunt fear is if the schools shut down they will be done for the year, done for the school year maybe even for the calendar year. So I’m very reticent to shut down schools,” de Blasio said.

Among his reasons for keeping schools open are the fact that poor kids who get their meals at schools, health care providers and first responders need a place to send their children, and unsupervised teens create health and safety concerns.

Each of these concerns is very real and represents bullets shot at BdB for his lack of wokeness and sensitivity. But what goes unnoticed as Bill’s shredded for NYC students’ myriad problems is the other side of the argument, this time reflected by the teachers’ union.

In a letter addressed “to the parents and guardians of our public school students,” United Federation of Teachers President Michael Mulgrew wrote, “Because of his irresponsible decision to keep the public schools open, Mayor Bill de Blasio can no longer assure the health and safety of our students and school communities.

“The mayor is recklessly putting the health of our students, their families and school staff in jeopardy by refusing to close public schools.

Just as the police union has used fear effectively to achieve its goals, the teachers’ union has as well. That doesn’t make them wrong and the fear unjustified, but it’s still used to whip up hysteria.

“The health and safety of our school community — and indeed the entire city — hangs in the balance.”

Do this or die is a time-honored cry. And so BdB, like his Long Island pals, pulled the plug.

As pressure from public health professionals, the teachers’ union and parents mounted, Mayor de Blasio and Gov. Cuomo brought the hammer down Sunday: The nation’s largest public school system has shuttered to slow the spread of the COVID-19 virus.

The decision was made. Whether this is the end of school for this year remains to be seen, but what is known is that other than closing the schoolhouse doors, they have no plan on what else to do.

“A variety of contingencies are being set up. They are far from perfect,” de Blasio said on CNN Sunday morning after a growing number of teachers, local elected officials and parents called for the closure.

“The difference between a functioning school system for over 1 million kids versus creating alternative centers for feeding or for the kids of health care workers, that kind of thing, if we got to that point we would improvise anything and everything,” de Blasio said.

“But it will not be by any means as good by definition as what we do every day when we have a functioning school system. But those contingencies are being built as we speak,” he said.

Far from perfect is a given. There is no perfect, but the fact is that there are no plans at all at this point. One might have thought that someone had given some consideration to the creation of contingency plans in advance of a crisis and that there are plans kept in some file cabinet somewhere to be pulled out when needed. Sure, they might not be exactly on target, since who could possibly plan for every contingency, but something, some sort of plan. Nope. They’ve got nothing.

At its most shallow, the issue is that when the choices are between life and death, you choose life and clean up the mess afterward, no matter how ugly the mess might be. If you’re dead, nothing else matters. But would another couple days to put together plans have helped? Can any plan suffice to meet the approval of the self-serving mob, for whom their cries of suffering overcome the voices of reason?

Mayor Bill de Blasio could have planned for this closing over the last couple of weeks. So too could the districts on Long Island. They didn’t. Not really. But then, is there any plan that won’t ultimately be condemned as failing whatever interest or identity group feels it didn’t accommodate them?

Crises will happen. Decisions have to be made. But what is the right decision when what’s good for the most people isn’t sufficiently good for the few? And what does the Mayor of New York City do when he knows that any choice will ultimately result in his condemnation? When you can’t win no matter what you do, do you heed the loudest voices or do what you believe to be the best for the most people?