U.S. Secretary of Education Betsy DeVos issued a letter to the top education brass of each state on Thursday, igniting a firestorm of angry responses.

At issue is a federal mandate that requires statewide summative assessments and school accountability, which were waived last spring by the U.S. Department of Education (DOE) as a result of the COVID-19 pandemic. Many state education leaders wanted the DOE to extend those waivers for the 2020-2021 school year.