AFTER EDIT: I just received in today's postal mail a mailpiece from a public advocacy organization (I'm not familiar with the organization) pointing out that current union contracts in Minnesota's public schools still require that school districts that have to downsize staff (as some must do as the number of school-age children in Minnesota declines) have to lay off teachers by seniority, not by effectiveness. This organization's policy argument is that any time a school district hires, lays off, or promotes teachers, it should do so on the basis of demonstrated helpfulness to learners learning, not by the order in which the teachers were first hired. That makes sense as a way to staff schools better to help learners, which is what teachers are all about.