Only 18 percent of students in Chicago’s public high schools can read at grade level. Only 19 percent are proficient in math. More than 60 percent of students in the district rely on their school for free or reduced-price lunches. If there is a school district in the United States whose students can least afford to be kept out of the classroom, it is Chicago.

And yet.

Chicago’s vast network of public schools have been closed for the past three days after members of the Chicago Teachers Union first refused to report to school on Wednesday. Seventy-three percent of those who voted in the union’s internal poll Tuesday supported moving to remote instruction until local infection rates drop or January 18, whichever comes first. In a New York Times report, union members cited “unsafe” conditions at the schools.

Chicago Public Schools have spent $100 million improving ventilation in their school buildings. More than 90 percent of its employees are fully vaccinated. Every employee who wants to receive the vaccine has had ample opportunity to do so. The notion that Chicago schools are particularly “unsafe,” at least as regards the transmission of the coronavirus, is not credible.

Elected Democrats realize—at a date far too late for both their electoral prospects and the well-being of children under their rule—that school closures are a non-starter for all but the most neurotic voters. They’ve changed their tune accordingly. Chicago Mayor Lori Lightfoot said she is “tired of the Groundhog Day appearance of everything that goes on with the Chicago Teachers Union leadership,” and called on teachers to defy their leaders. “I will not allow them to compromise the future of this generation of CPS students,” Lightfoot said. “That is not going to happen.”

Unfortunately for Lightfoot and public-school students in Chicago, the teachers’ union holds the cards. If its members don’t show up to school, there will be no in-person learning, no matter the mayor’s protestations.

Like every other major institution in American society, the Chicago Teachers Union is pandering to the most-unstable wing of its already-unstable membership. The neurotics are the tail that wags the dog.

The last time Chicago Public Schools went remote, there was a three-fold increase in failure rates among elementary-school students. If the union continues to hold Chicago’s students hostage, expect more of the same in the coming weeks.