Teachers in many districts are fighting for longer school closures, stronger safety requirements and limits on what they are required to do in virtual classrooms, while flooding social media and state capitols with their concerns and threatening to walk off their jobs if key demands are not met.

On Tuesday, the nation’s second-largest teachers’ union raised the stakes dramatically by authorizing its local and state chapters to strike if their districts do not take sufficient precautions — such as requiring masks and updating ventilation systems — before reopening classrooms. Already, teachers’ unions have sued Florida’s governor over that state’s efforts to require schools to offer in-person instruction…

With the academic year set to begin next month in much of the country, parents are desperate for teachers to provide more interactive, face-to-face instruction this fall, both online and, where safe, in person. But many unions, while concerned about the safety of classrooms, are also fighting to limit the amount of time that teachers are required to be on video over the course of a day.