The past decade may rank as one of the worst in the history of American education. It marks a stark reversal from what was once a hopeful story. At the start of the century, American students registered steady improvement in math and reading. Around 2013, this progress began to stall out, and then to backslide dramatically. What exactly went wrong? The decline began well before the pandemic, so COVID-era disruptions alone cannot explain it. Smartphones and social media probably account for some of the drop. But there’s another explanation, albeit one that progressives in particular seem reluctant to countenance: a...