Substitute teachers are in critically short supply and America’s school children may be short-changed because of it. Burbio, a service that tracks school websites, reported numerous school closings across Texas last week due to staff absences and substitute shortages. Many other states are experiencing similar problems. A 2021 national survey of 1,200 school district administrators and principals conducted by Frontline Education found 67 percent experienced a substitute teacher shortage. A nation-wide survey taken in November 2020 by the Education Week Research Center found that of the 913 public school administrators, principals, and teachers questioned, one-third said they could not find a substitute to cover half of teacher absences. Twenty-one percent said they could fill less than 25 percent of teacher absences. Eighty percent of the survey’s respondents reported leaving some classes uncovered. So that no classroom is ever unattended, the general practice has been to ask other teachers to give up …