Add this to the debate over whether kids should be back in school this fall. Illinois’ two largest teachers’ unions, the Illinois Education Association and the Illinois Federation of Teachers, yesterday said they may strike if local schools demand in-person classes. The unions wrote an open letter that said if back-to-school plans are not safe, they will act. The unions say their ‘entire weight’ will be used ‘in whatever way is necessary’ to deal with returning to school this fall.