Not everything worth doing should be done by the federal government. That may be the understatement of the millennium, but it’s the key to understanding why the current push for “common core” standards in education is a bad idea. Common Core is the latest wrinkle in a 20-year trend to raise standards and increase accountability in education policy. Perhaps inevitably, this trend has coincided with a growing federal role in setting educational standards and mandated testing. This movement has been bipartisan, with one of the largest expansions of federal authority occurring under President Bush’s 2001 No Child Left Behind Act. This law requires standardized testing of students attending schools that receive federal funds, although these tests are designed and administered at the state level.  Common Core actually began as a voluntary effort among states to provide guidance to educators on what students should know in each grade to be ready for college and compete in a globalized...