Bai: Teachers are vital public servants. Time for them to start acting like it.

It won’t be easy for President Biden to get America’s teachers back into public schools. Teachers unions are a powerful force in Democratic politics, and they’re resisting calls to return to classrooms where about half the nation’s kids ought to be sitting. When asked about the issue on Monday, Biden seemed to back up the unions, saying the onus was on districts and governments to make the classrooms safer. Behind closed doors, however, Biden’s message to the teachers should be straightforward and emphatic: You are vital, irreplaceable public servants. And it’s time you started acting like it.